TRB Annual Meeting Program

09-0275 - Performance of Three Popular Asphalt Pavement Rehabilitation Strategies
Session 679
This study analyzes the performance of three common hot mix asphalt rehabilitation strategies on 149 pavements over a period of seven years. All three strategies place two-inch overlays over the pavement to be rehabilitated. The first strategy includes an overlay on the existing pavement after sweeping the surface and applying a tack coat. The second strategy places the overlay after removing two inches of the existing pavement by cold milling. The third strategy places the overlay after treating the existing pavement using the heater scarification process. Performance was evaluated with respect to PG binder temperature range, traffic volume, overlay nominal maximum aggregate size, and climate. Data analyzed in the study was obtained from a pavement management system that is updated annually with respect to pavement condition. Results of this analysis indicate that two of the rehabilitation strategies perform approximately equal with one performing slightly better than the other, and both performing significantly better than the third. Polymer modified asphalts enhanced pavement performance depending on which rehabilitation strategy was utilized. Pavements were generally rehabilitated before reaching the zero service life threshold. However, when fatigue cracking was present in the original pavements, this was not the case. These pavements were rehabilitated at or above the zero remaining service life threshold. This indicates rehabilitation would have been warranted earlier in the life of these pavements. As a result, the expected life of the rehabilitation strategies utilized on these pavements may be shorter than could be expected had rehabilitation been done before distress reached this high level.
Scott Shuler, Colorado State University, scott.shuler@colostate.edu
Christopher Schmidt, Colorado State University

09-0825 - Methodology to Evaluate Quality of Pavement Surface Distress Data Collected from Automated Techniques
Session 679
Automated pavement data collection techniques are commonly used by highway agencies to collect pavement surface distress data at the network level. While an immense amount of data is collected at the network level, agencies realize that there is a lack of understanding in the quality of data that has been collected. Traditionally, either the overall pavement condition rating or individual distress ratings have been used to evaluate the quality of the condition data. However, each measure has its own pros and cons, rendering the use of a single measure inadequate. This paper presents a set of performance measures that can be used by highway agencies to quantify the quality of the collected and processed pavement condition data. The set of measures consists of (i) pavement condition rating and the hypothesis testing for differences; (ii) percentage cumulative difference in pavement condition rating over its entire range; and (iii) kappa statistics for individual distresses. This set of performance measures can be used to assess the effectiveness of an automated pavement condition data collection method and the effect of sampling on the pavement condition ratings obtained from automated techniques. Effectiveness of an automated technique is assessed against benchmark manual visual surveys. The performance measures offer a complete assessment of the effect of sampling on the overall pavement condition rating, its variation over the entire range, and the identification of individual surface distresses.
     Ghim Ping  Ong, Purdue University, ongr@purdue.edu
     A. Samy  Noureldin, Indiana Department of Transportation
     Kumares C. Sinha, Purdue University

09-1027 - Full-Scale Traffic Tests and Laboratory Testing Protocol for Determining Rapid-Setting Material Suitability for Expedient Pavement Repairs
Session 752
Numerous commercial-off-the-shelf (COTS) products have become avail¬able for small surface repairs in portland cement concrete (PCC) pavements that provide short set times, high early strengths, and good durability to withstand heavy loads. These materials have been used successfully for small repairs in the trans¬portation industry, and in industrial applications where the repair was less than 0.03 m3 (1 ft3). Applying these products for larger volume repairs while still achieving a trafficable surface within 3 hours of pavement repair has been a challenge. Experience gained from testing these products for full-depth repairs provides guidance for repair techniques that will expedite opening airfield or highway pavements to traffic and minimize the frequency of maintenance activities. An investigation conducted at the U.S. Army Engineer Research and Development Center (ERDC) in Vicksburg, MS examined 9 rapid-setting materials for repair of PCC pavements through laboratory characterization and full-scale traffic tests. Standard laboratory tests were performed to characterize the material properties over time and to provide a mechanism for assessing the material suitability for field repairs. Repairs with approximate volumes of 0.7 m3 (1.5 yd3) were constructed and evaluated under controlled traffic conditions to determine the ability of the repairs to support the 100 simulated passes of an F-15E aircraft within 3 hours of repair. Results of traffic tests identified 7 repair materials that met these criteria. A laboratory protocol for selection of rapid-setting materials was developed based on the laboratory and full-scale test results. This protocol will help prevent the selection of materials that are likely to perform poorly, therefore requiring extended traffic disruptions for additional repairs in the future.
     Lucy Phillips Priddy, U.S. Army Engineer Research and Development Center, lucy.p.priddy@usace.army.mil
     Sarah  Jersey, U.S. Army Engineer Research and Development Center
     Reed B. Freeman, U.S. Army Engineer Research and Development Center

09-1307 - Evaluation of LTPP Profile Data for Flexible Pavements
Session 679
The Long Term Pavement Performance (LTPP) program has collected longitudinal profile data for a wide variety of pavements nationally for almost 20 years. The program is managed by the Federal Highway Administration, which also maintains the LTPP database. Another portion of FHWA increased the testing frequency for longitudinal profile by state agencies for the HPMS from biannually to annually. This paper looks at the LTPP data to see if the increased frequency being required for HPMS is justified. The data sets used in the study were all General Pavement Studies (GPS) with either aggregate base or asphalt stabilized base. International Roughness Index (IRI) and the time between successful data collections were used to plot IRI versus time for each section. A polynomial of form ax2 + bx + c was fit for each site, and the polynomial was used to calculate the number of years to a 30 point change in IRI, using English units of inches per mile. Plots were also made of change in IRI versus the time between test events by climatic region. As has been reported by others, the largest contribution to future IRI is initial IRI. In all climatic zones, the time to reach a 30 point increase in IRI decreased with increasing initial roughness. Straight lines fit thru the change in IRI versus time between tests have very low slopes ranging from .0052 to .0096 points per day. Even at the maximum slope, it takes 3 years to reach a ten point change in IRI using English Units. Based on the LTPP data for GPS flexible pavements nationally, annual testing is not warranted.
Judith B. Corley-Lay, North Carolina Department of Transportation, jlay@ncdot.gov
Jeffery Mastin, North Carolina Department of Transportation

09-1564 - Use of Phosphoric Acid as a Modifier for Hot-Mix Asphalt
Session 541
The use of phosphoric acid to stiffen paving asphalt has become popular. Several premature paving failures have been attributed to its use, largely based on incomplete information. This has created uncertainty about the hidden pitfalls surrounding the use of this additive. The primary concerns are the effect of different grades of phosphoric acid, reaction with asphalt from different sources, accelerated aging of binders, increased moisture sensitivity and use with antistrip additives. This research seeks to address these issues. Data will be presented to show how the moisture sensitivity increases with increasing levels of acid modification. This is presented in terms of moisture being absorbed into binder and mastic samples as well as the leaching of phosphoric acid from gyratory specimens, a potential source of groundwater pollution particularly at high levels of acid modification. Preconceived notions about the use of phosphoric acid with alkaline antistrip additives and the effect on increased binder oxidation rates are also discussed. Phosphoric acid was found to not increase asphalt oxidation rates. Use with antistrip additives is perfectly feasible if the correct screening tests are conducted before use.
     Terence Stanley Arnold, Federal Highway Administration, terry.arnold@fhwa.dot.gov
     Susan P. Needham, SES Group & Associates
     John S. Youtcheff Jr., Federal Highway Administration

09-1913 - Measurement of Visibility Loss due to Splash and Spray: Comparison Between Porous Asphalt, Stone Matrix Asphalt, and Conventional Asphalt Pavements
Session 695
Road traffic accident is a major problem for the economy and society of ASEAN countries. In each year, road traffic accidents in Thailand cost millions of baht and inflict a large loss of life. Many of these accidents are caused by environmental or road conditions. Poor visibility on wet pavement is one cause of accidents. Accumulated water on wet pavement surfaces can create the “splash and spray” effect, resulting in visibility loss. The main objective of this study is to develop simple methods for measuring and comparing visibility loss between conventional dense-graded, Stone Mastic Asphalt (SMA), and Porous Asphalt (PA) pavements. Light Reduction Method (LRM) and Color Changing Method (CCM) were found to be the appropriate tests for visibility loss measurement. The test results from both LRM and CCM show that the visibility loss is significantly greater for conventional dense-graded pavement when comparing to SMA and PA pavements. It was found that the amount of water level, speed, and vehicle size significantly affect the visibility loss due to splash and spray. The models for predicting the percent of visibility loss was also developed and could be useful for the selection of pavement surface to reduce splash and spray under wet pavement conditions, and thus to improve road safety.
Pichaya Rungruangvirojn, Asian Institute of Technology, Thailand
Kunnawee Kanitpong, Asian Institute of Technology, Thailand, kanitpon@ait.ac.th

09-2283 - Evaluation of Warm-Mix Asphalt Produced with Double Barrel Green Process
Session 543
During the past three years, Warm Mix Asphalt (WMA) technologies from European countries have entered the North American market. European experiences with WMA technologies have indicated a significant reduction in mixture temperature, mixture viscosity, energy consumption and environmental emissions during asphalt mix production and placement in comparison with traditional hot mix asphalt (HMA). Based on North America experiences to date with these technologies, transportation agencies and HMA producers are unlikely to adopt WMA technologies solely for the reduction in manufacturing energy costs and environmental emissions, as these benefits do not cover the associated increase in investment and additive costs of WMA over HMA even in the most expensive North American energy markets. This paper presents an evaluation of the economic, environmental and mixture performance in order to assess the sustainability of WMA in North America. The paper examines the benefits, risks, investment and material costs, and sustainability associated with the different WMA technologies and specifically the Double Barrel® Green process. Included is an economic and mixture performance evaluation of WMA mixes containing reclaimed asphalt pavement (RAP) and manufactured shingle modifier (MSM™) produced with the Double Barrel® Green process during field trials in Vancouver, British Columbia.
Brent Middleton, Lafarge North America, Brent.Middleton@lafarge-na.com
Bob Forfylow, Lafarge North America

09-2520 - Application of Improved Crack Prediction Methodology in Florida's Highway Network
Session 679
With the growing need to maintain roadway systems amidst increasingly competitive resources while assuring safety and comfort for travelers, sound network-level decision-making becomes more vital than ever. A stochastic process known as Markov chain has been used extensively to capture the uncertainty associated with pavement performance over time and support this critical decision-making process. In applying Markov chain, this paper investigates the crack history of flexible pavements with an insight into the impacts of two primary factors contributing to the rapid deterioration of surface cracks in flexible pavements; excessive traffic loading and delayed maintenance and rehabilitation. Empirical results of the investigation are presented using the data from the Florida Department of Transportation¡¯s (FDOT) pavement condition survey database. The results show that the impacts of the above two factors are statistically different from one another in terms of the deterioration rate of Florida¡¯s pavements with respect to cracks. Hence the findings of this paper would assist the highway authorities in making more timely and efficient network-level decisions.
     Sahand  Nasseri, University of South Florida
     Manjriker  Gunaratne, University of South Florida
     Jidong  Yang, T.Y. Lin International, jidong_yang@yahoo.com
     Abdenour  Nazef, Florida Department of Transportation

09-2654 - Field and Laboratory Forensic Analysis of Reflective Cracking on Massachusetts Interstate 495
Session 295
In July 2007, the Massachusetts State Highway Department (MassHighway) began paving a pavement rehabilitation project involving placement of HMA over a section of Portland cement concrete (PCC) pavement on Interstate 495. The pavement rehabilitation consisted of a 50.0mm (2 inches) thick Leveling Course, followed by a 25.0mm (1 inch) thick Reflective Crack Relief Interlayer (RCRI), and then overlaid with another 50.0mm (2 inches) thick intermediate course consisting of a dense-graded hot mix asphalt (HMA) mixture that was identical to the Leveling Course. Due to time constraints on the project, approximately 30% of the PCC had only received the initial 50.0mm (2 inches) thick Leveling Course by the end of the 2007 paving season, with the remaining lifts scheduled for placement over the PCC in the Spring of 2008. Within approximately two months after placement, reflective cracking was observed in the area where only the initial 50.0mm thick Leveling Course had been placed. Approximately six months after the section that included the RCRI had been placed, reflective cracking was also observed. This paper summarizes a field and laboratory forensic effort that was aimed at determining the cause of the early reflective cracking on Interstate 495 in Massachusetts. Field testing, consisting of Falling Weight Deflectometer and coring of PCC pavement, were used to assess the PCC joint performance in the vertical and horizontal deflection modes. Laboratory testing was conducted on laboratory prepared HMA and evaluated for cracking resistance under vertical and horizontal deflections and test temperatures that simulated field conditions. The results of the study clearly indicated that the dense-graded HMA mixture used as the Leveling and intermediate layers could not withstand the vertical and horizontal deflections of the PCC joints taking place on I-495. This paper also provides a general framework that can be used to assess the compatibility that different HMA mixtures may have with RCRI mixtures when intended for use in composite pavements, which can be utilized for mixture selection/design prior to field placement.
     Thomas A. Bennert, Rutgers University, bennert@eden.rutgers.edu
     Michael  Worden, SemMaterials, L.P.
     Matthew  Turo, Massachusetts Highway Department

09-2693 - An Investigation of the Curing Mechanism of Foamed Asphalt Mixes Based on Micromechanics Principles
Session 543
This study investigated the curing mechanism of foamed asphalt mixes, based on which proposed standard curing procedures that are appropriate for use in project level mix design. Mixes with various asphalt and portland cement contents were subjected to two relatively extreme curing conditions, and multiple types of laboratory tests were performed. It was found that portland cement enhances certain properties of foamed asphalt mixes by strengthening the mineral filler phase, with the curing mechanism similar to that of normal cement treated materials. The curing mechanism of foamed asphalt mastic is primarily related to water evaporation. The bonding between asphalt mastic and aggregate particles cannot fully develop until most of the water retained at the interface evaporates. This bonding, once formed, is only partially damaged by reintroduced water. This mechanism was supported by direct fracture face observations on tested specimens. Two curing methods are proposed as standard procedures for project level mix design. The proposed strategy tests materials under two extreme conditions instead of attempting to precisely replicate field conditions, allowing the engineer to judge whether the tested materials suit the actual range of conditions at a specific project site. Portland cement or other appropriate active filler is recommended to be used in conjunction with foamed asphalt, which has a slow curing rate under most field conditions, to obtain early strength and allow early opening to traffic.
     Pengcheng  Fu, University of California, Davis, pfu@ucdavis.edu
     David  Jones, University of California, Davis
     John  Harvey, University of California, Davis
     Felipe  Halles, Pontificia Universidad Catolica de Chile

09-2946 - Development of Simplified Approach for Assessing Level of Safety of Highway Network Associated with Pavement Friction
Session 679
One of the most important indicators of level of service for a highway network is safety. Each year, thousands of motorists across North America are involved in motor vehicle collisions, which result in property damage, congestion, delays, injuries and fatalities. In Ontario, the Ministry of Transportation (MTO) is responsible for the maintenance and construction of approximately 39,000 lane-kilometres of highway. In 2004, the province estimated the value of the total highway system at $39 billion dollars. The MTO estimated that in 2002, vehicle collisions in Ontario cost the province nearly $11 billion. It also estimated that for every dollar spent on traffic management, 10 times that amount could be saved on collision-related expenditures, including health care and insurance claims. The safety of highway networks are usually assessed using various levels of service indicators such as ride quality (IRI), surface friction (SN), or number of collisions. This paper presents a simplified framework for assessing the level of safety of a highway network in terms of the risk of collision based on pavement surface friction. The developed safety framework can be used by transportation agencies (federal, state, provincial, municipal, etc.) or the private sector (consultants, contractors, concessionaires, etc.) to evaluate the safety of their highway networks and to determine the risk or probability of a collision occurring given the level of friction along the pavement section of interest.
     Amir  Abd El Halim, Stantec Consulting, amir.abdelhalim@stantec.com
     Susan Louise Tighe, University of Waterloo, Canada
     Tom  Klement, Ontario Ministry of Transportation, Canada

09-2973 - Storage Stability and Effect of Mineral Surface on Polyphosphoric Acid-Modified Asphalt Binders
Session 541
Polyphosphoric acid (PPA) is a commonly used modifier for asphalt binders. Successful modification of an asphalt binder with PPA is intended to improve the high temperature stiffness of the material without negatively affecting the low temperature properties. The overall mechanism of reaction between asphalt and PPA it is not very well understood, although it seems to be generally accepted that the PPA reacts with the asphaltene fraction of the binders. This study investigates two different asphalt binders, one with high asphaltene content, and one with low asphaltene content. The selected binders are modified with PPA and mixed with two different fillers to measure the rheological properties of both the modified and unmodified binders using the Dynamic Shear Rheometer. The surface area of the samples, the high-temperature storage time, the asphaltene content of the binders, and contact with mineral surface are all important factors examined in this study. By varying these parameters, the changes in rheological behavior of the liquid binder during storage are measured and analyzed. In addition, the effect of contact with mineral surface is investigated to reflect the possible interactions that could take place in asphaltic mixtures during processing and handling at high temperature. The results indicate that surface to volume ratio can have significant effects on aging of unmodified and modified binders. The PPA modification, however, can result in more stability during storage at high temperature. There also appears to be an important influence of contact with mineral surface on the changes in rheological properties induced by the addition of PPA.
     Codrin  Daranga, University of Wisconsin, Madison, daranga@wisc.edu
     Cristian  Clopotel, University of Wisconsin, Madison
     Adekunle  Mofolasayo, University of Wisconsin, Madison
     Hussain U. Bahia, University of Wisconsin, Madison

09-3157 - Practical Use of Multiple Stress Creep Recovery Test: Characterization of Styrene-Butadiene-Styrene Dispersion and Other Additives in PMA Binders
Session 541
The rheological properties of SBS modified asphalt binders (SBS-PMAs) depend on formulation variables. The most sensitive among them may be listed as polymer amount, cross-linking agent amount (%), and other additives (PPA). The dispersion of SBS in an asphalt binder depends on blending time and temperature and base asphalt binder compatibility. In this study an incompatible and a compatible base asphalt binder were selected and modified with various amounts of SBS. Elemental sulfur was used as a cross-linking agent in various proportions. Other additives such as PPA at 0.5% concentration and wax at various amounts were also used. High shear blends of SBS-PMAs were made in the laboratory by varying blending time until an optimum dispersion of polymer was obtained. The dispersion of the polymer was studied using a fluorescence microscope. MSCR test was used to study creep and recovery behavior of these modified binders. It was found that MSCR test results (Jnr and %recovery) were able to characterize the extent of dispersion of SBS in these PMAs. This implies that a fundamental test method is now available to discriminate between the ‘dump&stir’ type PMAs and those that have been optimally dispersed. This presentation discusses the effect of SBS dispersion and other additives on the MSCR test results.
John A. D'Angelo, D’Angelo Consulting, LLC
Raj N. Dongre, Dongre Laboratory Services Inc., rajdongre@dongrelabs.com

09-3228 - Precision of AASHTO TP62-07 for Use in Mechanistic-Empirical Pavement Design Guide for Flexible Pavements
Session 778
In the Mechanistic Empirical Pavement Design Guide (MEPDG), one of the most important material inputs for designing flexible pavements is the dynamic modulus (E*). Currently, the American Association of State Highway Officials (AASHTO) has provided a provisional test specification for measuring the dynamic modulus of hot mix asphalt mixtures entitled, AASHTO TP62-07, Standard Method of Test for Determining Dynamic Modulus of Hot-Mix Asphalt (HMA). Under AASHTO TP62-07, recommendations are provided for sample preparation/compaction, measurement system, testing conditions/procedures and calculations. Unfortunately, information does not exist regarding the general precision of the test method. With so many different test machines capable of conducting AASHTO TP62-07 and the importance of dynamic modulus in flexible pavement design, an understanding of the general precision of the test method and its influence on the MEPDG is needed. This paper describes the results of a round robin study conducted to address the need for a precision-type statement for AASHTO TP62-07. Seven (7) laboratories, all having equipment compliant to the specifications in AASHTO TP62-07, were asked to laboratory age, compact, prepare, and test six (6) hot mix asphalt test specimens according to the provisions in AASHTO TP62-07. A statistical analysis was conducted on the test data in a precision statement environment. Based on the test results, an initial precision statement for AASHTO TP62-07 was generated and presented. The test results for the seven (7) different laboratories were also used as inputs in the MPEDG to evaluate the relative differences in predicted pavement distresses. Results from the precision evaluation were used to recommend modifications to AASHTO TP62-07 to promote greater precision among different testing laboratories and the results were re-evaluated in the MEPDG.
Thomas A. Bennert, Rutgers University, bennert@eden.rutgers.edu
Stacy Goad Williams, University of Arkansas, Fayetteville

09-3510 - Using the Dynamic Modulus Test for Moisture Susceptibility Evaluation of Asphalt Mixtures
Session 540
Stripping in Hot Mix Asphalt (HMA) is assessed by AASHTO T 283 using the indirect tensile strength test. The Tensile Strength Ratio (TSR) is used as the criteria for strength retention after sample conditioning. In recent years, the Dynamic Modulus E* test, conducted per AASHTO TP 62-03 has gained wider use in the pavement community. This is because it is a major input into the Mechanistic Empirical Pavement Design Guide (MEPDG), and is also being used as a simple performance test indicator. The objective of this study was to assess if the Dynamic Modulus E* laboratory test can be used as a replacement test property for the indirect tensile strength in AASHTO T 283. Since the E* test is non destructive, unlike the indirect tensile strength test, the advantage would be that the same specimens could be used before and after moisture conditioning. The scope of work in this research included conducting laboratory testing program on several types of asphalt mixtures using both test procedures. All of the mixtures were obtained from actual construction projects in the field. A unique aspect of this study is that some of the mixtures actually failed in the field by stripping. The E* tests were used to determine the percent retained stiffness, a term that was referred to as E* Stiffness Ratio, or ESR. Results of both TSR and ESR conducted on the same mixtures were compared and statistically analyzed. The analysis indicated that there was no statistical significant difference between the measured TSR and ESR values for the same mixture. The correlation obtained between the two ratios had good measures of accuracy. It was concluded that the ESR can potentially replace TSR testing to assess field moisture damage for asphalt mixtures. The recommendation was to continue with the testing program and expand the database for further future analysis.
     Atish Anil Nadkarni, Arizona State University, atish.nadkarni@asu.edu
     Kamil E. Kaloush, Arizona State University
     Waleed Abdelaziz Zeiada, Arizona State University
     Krishna Prapoorna Biligiri, Arizona State University

09-3683 - Forensic Investigation of Pavement Failures due to Moisture on Interstate Highways in Oregon
Session 295
In the last several years a number of major interstate and smaller projects in Oregon exhibited significant pavement distress that appeared to be associated with moisture damage within months following a rehabilitation activity. The premature failures prompted the Oregon Department of Transportation (ODOT) to fund a study to investigate interstate highway projects to determine the conditions and mechanisms that led to the premature failures. This paper documents forensic investigations of five Oregon interstate highway projects. Field investigations as well as laboratory testing of cores obtained from four of the five projects are documented. Improper tack coat or failure, permeable dense-graded layers, stripping, inadequate drainage, and, possibly, inadequate compaction of dense-graded material were identified as the likely root causes of the observed rutting problems on the projects that were investigated.
Todd Scholz, Oregon State University, todd.scholz@oregonstate.edu

Concrete Materials

09-0358 - Sustainable Concrete Through Reuse of Crushed Returned Concrete
Session 563
Every year, it is estimated that 2% to 10% (average of 5%) of the estimated 455 million cubic yards of ready mixed concrete produced in the USA (est. 2006) is returned to the concrete plant. The returned concrete in the truck can be handled in several different ways. A common approach is to discharge the returned concrete at a location in the concrete plant for processing (Figure 1). The hardened discharged concrete can be subsequently crushed by a crusher (Figure 2) and the coarser material can be reused as base for pavements or fill for other construction. However it is not easy to utilize the material finer than 2 inches (Figure 3). A research project was undertaken by the NRMCA Research Laboratory to study the use of crushed returned concrete, referred as Crushed Concrete Aggregate (CCA), as a portion of the aggregate component in new concrete. The project was funded by the Ready Mixed Concrete Research and Education Foundation (RMCREF). Demolishing old concrete structures, crushing the concrete and using the crushed materials as aggregates is not new and has been researched to some extent. This material is generally referred as Recycled Concrete Aggregates (RCA). However, RCA is different from CCA as construction debris tends to have a high level of contamination (rebar, oils, deicing salts, and other building components). CCA on the other hand is prepared from concrete that has never been in service and thus likely to contain much lower levels of contamination. The main objective of the research project was to develop technical data that will support the use of CCA from returned concrete by the industry and to provide guidance on a methodology for appropriate use of the material. Such a step can help the ready mixed concrete industry to save an estimated $300 million/year in operating costs. In addition, it will reduce landfill space by as much as 845 – 10 feet high football fields every year. The use of CCA could also help attain points under systems like the Leadership in Energy and Environmental (LEED) for certifying building projects for sustainable construction. This short article summarizes the key findings from the 20 month study. The complete reports can be downloaded from either one of the following locations http://www.rmc-foundation.org/newsite/index.htm and http://www.nrmca.org/research/eng_articles.asp.
Karthik Obla P.E., National Ready Mixed Concrete Association, kobla@nrmca.org

09-0418 - Evaluation of D-Cracking Preventive Measures in an Ohio Test Pavement
Session 639
A test pavement located on part of State Route 2 near Vermilion, Ohio, was built in 1975 with sections designed to investigate the role of pavement design and materials variables that include aggregate source and size, subbase drainage systems, pavement joint design, subbase materials, joint sealants, cement, type of cure, and joint spacing on D-cracking. In 1998, this study was initiated to better understand concrete durability among the different composition variables of the pavement sections after 23 years of performance. This study established a methodology to analyze the pavement sections, gathered data, and analyzed the data using SAS statistical software. Significant findings on the variables affecting the performance of pavement sections were obtained. Key findings show the impact of aggregate source and size, joint sealants, and vapor barriers on pavement D-cracking performance and overall pavement performance. Based on the findings of this research, the requirement to use larger size aggregate in concrete pavement was incorporated into the Ohio Department of Transportation (ODOT) 1997 Construction and Material Specifications. Also, the 2009 ODOT specifications will eliminate the requirement for joint sealing in new concrete pavement based on in part on the findings of this study.
John Dryden, University of North Florida, j.dryden@unf.edu
L. Travis Chapin P.E., Bowling Green State University

09-1149 - Long-Term Chloride Penetration Resistance of Bridge Decks Made with Silica Fume Concretes
Session 718
With support from the Silica Fume Association, cores were obtained in 2001 and 2002 from four concretes from bridge decks in New York State and one in Ohio which were 15 years old and which had been exposed to de-icing salts. The bridge in Ohio was 15 years old and made with silica fume concrete (477 kg/m3 cementitious materials with 14.3% silica fume, 0.33 w/cm). The New York bridges included a 6 year old Portland cement concrete (0.42 w/c, 400 kg/m3), a 6 year old, 0.40 concrete with 20% F-fly ash and 6% silica fume (400kg/m3), a 7 year old, 11% silica fume, 0.37 concrete (455 kg/m3), and a 12 year old silica fume concrete overlay ( 6% silica fume, 0.40, 400kg/m3). The cores were tested for chloride penetration profiles using mm profiling, chloride bulk diffusion by ASTM C1556, rapid chloride penetration (ASTM C1202), and the depth of cover was noted, where visible. The results show that all of the silica fume concrete decks had high chloride penetration resistance, with all full depth decks having between 290 and 690 coulombs on average, while the portland cement concrete had 3900 coulombs. Predicted time-to-corrosion service life, using the Life-365 program, gave residual life estimates of between 30 and 61 years for the silica fume concretes. A portland cement concrete, used as a control, was found to be likely subject to corrosion at the time of coring. Predicted residual service lives based on extrapolation from existing chloride penetration profiles gave longer estimates by 10-years on average for the 3 new new bridges made using silica fume concrete.
     Robert Douglas Hooton, University of Toronto, Canada, hooton@civ.utoronto.ca
     Evan C. Bentz, University of Toronto, Canada
     Tony  Kojundic, Elkem Materials

09-2187 - Performance of Rigid Pavements Containing Recycled Concrete Aggregates: 2006 Update
Session 639
A 1994 field survey of pavements containing recycled concrete aggregates (RCA) constructed in Connecticut, Kansas, Minnesota, Wisconsin and Wyoming was undertaken. These pavements were resurveyed during the summer of 2006 to update their performance after being subjected to 12 more traffic years. Additional pavements made with RCA from Illinois and Iowa were also observed in 2006. Although the recycled pavements contain higher mortar contents, There was no clear correlation between recycled pavements higher total mortar content with cracking distresses in either survey, although one recycled pavement did exhibit more cracking than the control pavement. Overall there was little difference between the 1994 and 2006 surveys. Several pavements were rehabilitated by adding dowels for load transfer. These pavements are performing exceptionally well showing rehabilitation techniques normally applied to conventional concrete works effectively on recycled pavements. Laboratory evaluation of field cores showed 10 of the 16 pavements surveyed were found to have alkali silica reaction (ASR), possibly explaining why they were originally recycled. Eight of these pavements were shown to have significant remaining expansion potential and are expected to continue expanding. All pavements identified with ASR and D-Cracking showed field performance equivalent to their controls and pavements without distress. The recycled pavements have performed comparably with their controls. For instance, present serviceability rating (PSR) was found to be similar for the recycled and control sections. Likewise the recycled pavements that incorporated RCA derived from D-cracked and alkali-silica reactive (ASR) concrete appears to be performing at least equivalent to the original pavements. Keywords: recycled concrete aggregate, pavement performance, pavement recycling, concrete recycling, field evaluation, alkali silica reaction, d-cracking.
     David Lee Gress, University of New Hampshire, david.gress@unh.edu
     Mark  Synder, Consultant
     Jeffrey  Sturtevant, Whitney Bailey Cox & Magnani, LLC

09-2685 - Treatment of Structures with Alkali-Silica Reactive Distress with Lithium Nitrate: Case Studies
Session 639
Lithium compounds have been found to be effective in reducing expansion of small, ASR-affected laboratory specimens, but there have been little, if any, data showing that lithium compounds are effective in field applications. The research described in this paper aims to fill in this gap in knowledge and focuses on the treatment of ASR-affected structures in the United States. The findings of this study show that topical applications of lithium nitrate are ineffective in reducing ASR-affected due to a lack of penetration of the lithium solution. Vacuum impregnation of lithium in field structures was also found to be ineffective, again due to a lack of lithium penetration. Electrochemical methods of driving lithium compounds into were found to be quite effective in increasing lithium penetration, but the observed migration of sodium and potassium from within the concrete to the reinforcing steel may negate the effects of increased lithium penetration.
     Kevin J. Folliard, University of Texas, Austin
     Michael  Thomas, University of New Brunswick, Canada, mdat@unb.ca
     Benoit  Fournier, Natural Resources Canada
     Jason  Ideker, University of Texas, Austin
     Bradley  East, University of Texas, Austin

09-3855 - Can Soy Methyl Esters Reduce Fluid Transport and Improve the Durability of Concrete?
Session 687
Many durability problems in concrete are caused by the transport of water or fluid containing aggressive ions. As a result, many seek to reduce the absorption and flow of fluids in concrete through the use of admixtures or topical sealants that refine or block pores. This paper presents results of a pilot study that evaluated the potential use of soy methyl ester – polystyrene blends (SME-PS) as both an admixture and/or a topical treatment. Results are presented for tests on the fresh properties, hardened properties, and transport properties of concrete containing SME-PS. Dramatic reductions in fluid absorption can be obtained with SME-PS, with little noticeable influence on set time, strength, or shrinkage. Eventually the application of SME-PS to concrete may have the potential to be used as a method to penetrate into the pore structure at saw-cuts and reduce long term damage.
     Kevin  Coates, Purdue University, kcoates@purdue.edu
     Samia  Mohtar, Purdue University
     Bernard  Tao, Purdue University
     William Jason Weiss, Purdue University

Construction

09-0357 - Design and Construction of Sustainable Pavements: Austrian and German Two-Layer Concrete Pavements
Session 243
There are a number of recent efforts in pavement research in the United States to create new sustainable technologies and designs using composite pavements—that is, pavements with heterogeneous asphalt and/or concrete layers resulting from new construction. While there are a number of asphalt-over-concrete composites in the United States, in the case of two-layer portland cement concrete (PCC) pavement very little American research and expertise exists its being a widely accepted solution for pavements in the European Union. This experience is described in this paper in terms of German and Austrian case studies. After a description of these case studies, the paper discusses major benefits of two-layer PCC, key factors for the success of two-layer PCC in the United States, and potential challenges in importing, adapting, and implementing German and Austrian techniques.
     Derek  Tompkins, University of Minnesota, Twin Cities, tompk019@umn.edu
     Lev  Khazanovich, University of Minnesota, Twin Cities
     Michael I. Darter, Applied Research Associates, Inc.
     Walter  Fleischer, STRABAG AG, Germany

09-1514 - Hot-Mix Asphalt Sampling Techniques and Methods of Acceptance: State Department of Transportation’s Practice
Session 594
Hot-mix asphalt (HMA) sampling is a critical step in quality control and quality assurance (QC/QA) programs to ensure that the tested material is representative of the installed product. Samples of HMA in Illinois are currently taken from a truck at the plant. This sampling method allows for a quick turnaround time since the QC laboratory is usually located at the plant. However, it may be difficult to obtain a representative sample since most of the sample is taken from the top of the pile and on the side closest to the sampling platform. In addition, this sampling method does not account for any additional asphalt absorption taking place during transportation and placement. The concept of moving the sample location to the job site offers the potential to address the weaknesses cited above. However, there are a number of different approaches, each with advantages and disadvantages. The objective of this study was to produce a review of successful methods and practices currently used to sample HMA during production and installation. This included visiting other states and collecting sufficient data to draw a final recommendation for the optimum technique to be adopted for HMA sampling in Illinois. The conclusion of the field visits is that sampling behind the paver is being successfully conducted by many states without difficulty. Based on the site visits conducted in this study, the roadway sampling procedure adopted by Michigan DOT was recommended for possible implementation in Illinois. In addition to this sampling technique, sealed bags adopted by Iowa DOT may be used, if necessary, to safely transport samples from the field to the laboratory.
     Mostafa A. Elseifi, Louisiana State University, elseifi@lsu.edu
     James  Trepanier, Illinois Department of Transportation
     Hal  Wakefield, Federal Highway Administration
     William  Pine, Heritage Research Group
     Abdul  Dahhan, Illinois Department of Transportation

09-1956 - Evaluation of Vacuum Drying for Determination of Bulk Specific Gravity of Hot-Mix Asphalt Samples
Session 594
Determination of bulk specific gravity (Gmb) of bituminous paving mixture is an important part of the Superpave mix design system and construction quality control/ quality assurance programs. Two problems commonly associated with AASHTO T 166 are the time it takes to dry test specimens and potential damage to the sample caused by drying at elevated temperatures. A vacuum drying technique has been developed to overcome these shortcomings. Field core samples and laboratory compacted samples of dense graded HMA and SMA were obtained for testing. The objectives of the study were to determine if dry mass and resultant Gmb of laboratory compacted and pavement core samples determined using vacuum drying procedures produces statistically similar results to AASHTO T 166 procedures. A second objective was to compare the dry mass obtained from AASHTO T 166 Method A to that of Method C. Comparisons of the means were made using ANOVA techniques along with paired t-testing. The practical significance of any statistically different results was also evaluated by using the precision statement of AASHTO T 166 (5). Results indicated that vacuum drying is an acceptable procedure for determining dry mass and bulk specific gravity of HMA samples.
Stephen Cross, Oklahoma State University, steve.cross@okstate.edu
Gyanendra Pokhrel, Oklahoma State University

09-2679 - Stiffness-Based Assessment of Pavement Foundation Materials Using Portable Tools
Session 512
Traditional pavement quality assurance has been performed using soil density and moisture content. Implementation of new mechanistic design methods calls for measuring the resilient modulus of constructed layers to determine if it matches the modulus used during the pavement design process. Several tools have been marketed for this purpose in recent years. Eleven soil test beds were constructed at the U.S. Army Engineer Research and Development Center (ERDC) to evaluate three of these tools. The study showed that the tools were simple to use and generally obtained repeatable results, but additional information regarding the true nature of the modulus measured by these tools is required to implement their use.
Sarah Jersey, U.S. Army Engineer Research and Development Center, sarah.r.jersey@usace.army.mil
Lulu Edwards, U.S. Army Engineer Research and Development Center

09-2825 - Dowel Alignment Constructability Evaluation In Portland Cement Concrete Pavements
Session 243
Although dowel bars are an essential design feature of jointed concrete pavements (JCP) to prevent pumping and faulting, limited studies that deal with the constructability of dowel alignment have been conducted. With the emergence of MIT Scan-2 as a non-destructive, robust method of locating dowels, it is now possible to efficiently evaluate construction quality of dowel bar placement, without damaging the newly constructed pavement. This paper presents a brief review of the results of recent field studies that are aimed at examining the constructability of doweled joints in concrete pavements. The dowel bar alignment data collected in this study encompasses a wide range of design and environmental conditions, and shows that alignment within reasonable levels, considering equipment, mix design, as well as workmanship and consistency is achievable in the field. Distress and performance analyses show that within these levels of misalignment, the pavement performance is not significantly affected. However, since construction errors are not uncommon, it is also reasonable to evaluate the effects of misalignments outside the typical tolerance limits. A comprehensive evaluation of the effects of dowel bar misalignment on pavement performance was conducted under NCHRP Project 10-69 to provide guidelines on dowel placement tolerance.
     Shreenath  Rao, Applied Research Associates, Inc., srao@ara.com
     Kyle  Hoegh, University of Minnesota, Twin Cities
     H. Thomas  Yu, Federal Highway Administration
     Lev  Khazanovich, University of Minnesota, Twin Cities

09-2891 - Development of a Decision Model for Selection of Appropriate Timely Delivery Techniques for Highway Projects
Session 240
On-time project performance is an important goal at the Oregon Department of Transportation (ODOT); pressure from two key constituents—the Legislature and trucking interests—creates even stronger focus on this goal. Currently, statistics indicate that less than 50% of ODOT projects complete within their originally contracted time of performance; further, project delay causes uncertainty about exactly when traffic delays may occur on a given stretch of highway, making it difficult to make the public aware of these delays far in advance. The primary “umbrella” method used to ensure on-time performance in standard ODOT contracting is liquidated damages. Often this amount is difficult to determine, so the assessment value is usually a matter of some judgment. In practice, liquidated damages are not seen as effective incentive and are rarely assessed. Other contracting and management methods which focus on encouraging time performance have been identified, but are used sporadically. Implementation of a system that creates better awareness of alternative schedule-delivery methods and that provides a consistent method for choosing among these methods would improve ODOT’s schedule performance. This paper discusses the results of a research project (ODOT SPR-646), designed to develop a means of selection among various available alternative methods for ensuring timely project delivery, given a specific project profile—using a selection model that is stable and scalable.
David N. Sillars, Oregon State University, david.sillars@oregonstate.edu

09-3357 - Methods for Evaluating Longitudinal Joint Quality in Asphalt Pavements
Session 594
Longitudinal joint quality is essential to the successful performance of hot-mix asphalt (HMA) pavements. Longitudinal joints have received a considerable amount of attention during recent years, as many state agencies are moving toward the implementation of longitudinal joint specifications. Most measures of joint quality are based on density determinations. However, distress at the joint is caused by the ability of air and water to enter the pavement structure – an action that is directly related to the permeability of the joint. In other words, density alone may not be sufficient for describing the quality of a longitudinal joint. The objective of this study was to identify the most appropriate test method (or methods) for describing HMA longitudinal joint quality. Three projects were selected for the study, and four testing stations were identified for each project. At each station, a number of test methods were performed at the longitudinal joint and to either side of the joint in order to assess the ability of each test method to properly discriminate between levels of joint quality. Multiple measures of density, permeability, and gradation were obtained at each testing station. Overall, the method providing the most accurate predictions of joint quality with the greatest level of discrimination was the CoreLok method for determining the bulk specific gravity of field cores. Thus, it was recommended that the CoreLok method be considered for the determination of field core density in the evaluation of longitudinal joint quality.
     Stacy Goad Williams, University of Arkansas, Fayetteville, sgwill@uark.edu
     Ashly  Pervis, University of Arkansas, Fayetteville
     Leela Soujanya Bhupathiraju, University of Arkansas, Fayetteville
     Annette  Porter, University of Arkansas, Fayetteville

09-3659 - Case Studies On Processes Involved In The Production And Placement Of High Rap Asphalt Concrete Mixes In 2007 On Selected Routes In Virginia
AFH60
This paper presents the documentation of Recycled Asphalt pavement processes in selected plants that were involved in the production of High RAP mixes for plant mix schedules which were placed in 2007 in the state of Virginia. A description of the processing of RAP at different plants is given and how the production of the high RAP material (reclaimed asphalt pavement which make up 20% or more of the asphalt mix) was monitored at the plants and the field on the selected routes in the state of Virginia. The types of asphalt plants operated by the different contractors are discussed showing how quality control process are monitored in High RAP production. Process control charts were shown for the RAP materials in one of the selected plants in addition to laboratory testing results. Results show the placement of the High RAP went well and field monitoring mechanisms are being put in the place to continue monitoring these sites for long term performance
     Alexander Kwasi Appea, VDOT, Alexander.Appea@VDOT.Virginia.gov
     Todd  Rorrer, VDOT
     Trenton  Clark, Virginia Department of Transportation

Design

09-2548 - Development and Validation of Methodology to Evaluate Unpaved Road Condition Based on Objective Distress Measures
Session 244
The condition of unpaved roads has been commonly assessed through qualitative distress measures. The relative effect of different defects over the road condition has not been considered consistently by some methodologies, or else, their application is limited to the conditions where they were developed. During 2007, the Ministry of Public Works of Chile (MOP) and a private consultant developed the study “Unpaved Roads Distress Models”. The scope of the study was to gain experience and understanding of unpaved roads behaviour. The main objective of the work presented in this document is the development and validation of a methodology to evaluate the condition of unpaved roads based on objective measures of distress, drainage and profile characteristics. The scope was to design a versatile tool, applicable to any location, following a simple procedure and under cost-effective survey techniques. The approach considered the development of condition models obtained from a questionnaire applied to a professional panel. The panel had to rate the condition of earth and gravel roads under different scenarios. These scenarios combined several levels of distress, drainage conditions and profile characteristics. The relative effect of each of these over the road condition was obtained from multiple linear regression analysis. Equations representing the Unpaved Condition Index (UPCI) and condition limits were developed for unbound gravel, stabilized gravel and earth roads, subject to three different climates (dry, Mediterranean and humid). UPCI equations and condition limits were validated successfully, resulting in a reliable and versatile methodology to assess unpaved roads condition.
     Alondra  Chamorro, University of Waterloo, Canada, machamor@uwaterloo.ca
     Hernan Eduardo de Solminihac, Pontificia Universidad Católica de Chile
     Mauricio  Salgado, APSA, Chile
     Ernesto  Barrera, Ministerio de Obras Públicas de Chile

09-3333 - Balancing Urban Driveway Design Demands Based on Stopping Sight Distance
Session 484
Many roadways located in urban areas, especially dense commercial areas, are subjected to on-street and adjacent off-street parking demands; however, local access via driveways is an essential component of these complex urban corridors. Vehicles entering and exiting these driveways and the interaction of these vehicles with parked cars, other moving motorized vehicles, bicycles, and pedestrians present challenges for a safe and efficient roadway corridor. The location and design of these driveways, together with parking and bicycle facilities, generate sight distance challenges that impact both pedestrians and bicyclists. This paper investigates the type and nature of impacts, including conflicts, sight distance, operations, and safety at driveway locations as they relate to pedestrians, bicyclists and drivers. The paper also analyzes appropriate design geometrics to provide adequate sight distance for safety at driveways with and without bicycle lanes. Parked vehicles often obstruct the driver’s view of legally approaching motor vehicles and bicycles. In many locations, vehicles exiting driveways must edge out into the active travelway before the driver has an unobstructed view. The driveway locations and design analysis demonstrates the value of bicycle lanes in providing enhanced sight distance. Current practices permit the longitudinal placement of on-street parking too close to driveways. For safety reasons, agencies should consider excluding on-street parking on roads with bike lanes when speeds exceed 30 mph so as to provide adequate sight distance without creating sporadic on-street parking spacing. Roads that do not have bike lanes present should exclude on-street parking when speeds exceed 25 mph.
     Karen K. Dixon, Oregon State University, karen.dixon@oregonstate.edu
     Ida  Van Schalkwyk, Oregon State University
     Robert Davis Layton, Oregon State University

09-3488 - Improved Sight Distance Model for Sag Vertical Curves with Overpasses
Session 435
On sag vertical curves uderpassing a structure, the fascia of the structure may cut the line of sight and limit the available sight distance. The current model of the American Association of State Highway and Transportation Officials (AASHTO) for symmetrical sag curves with overpasses is intended for overpasses that lie close to the point of vertical intersection (PVI) on long sag curves. This paper presents an improved model that provides the exact minimum sight distance (Sm) for any conditions, including non-centered overpasses and short sag curves that are typical in urban areas. The model explicitly includes as variables the overpass location, the overpass width, and the configuration of the first and second grades of the sag vertical curve. The model is formulated using mathematical optimization that involves an objective function and constraints. The objective function minimizes the available sight distance subject to constraints involving the geometry of the curve and the overpass. The model is spreadsheet-based and is solved using powerful optimization software. Application of the model was illustrated using some examples and the results show that the AASHTO model may underestimate Sm by10%–30%. A closed-form model for the minimum sight distance on single-arc asymmetrical sag curves is also presented for Sm > L. The proposed models provides a friendly, flexible, and accurate tool for sight distance analysis and should be of interest to highway designers and practitioners.
Said Easa, Ryerson University, Canada, seasa@ryerson.ca

Energy and Climate Change

Geology and Earth Materials

09-0537 - Performance of Pavement Aggregate Base Courses in North Carolina
Session 235
North Carolina DOT owns and maintains a system of 79000 miles, which range from interstate to very low volume roadways. The state is rich in quarries, and aggregate base course has been a mainstay of paving for roadways on new location for many years. This paper uses the pavement management system (PMS) data to evaluate the performance of three categories of aggregate base pavements based on the thickness of hot mixed asphalt placed over the aggregate base: thin, mid-range, and thick. Sections of pavement and their performance measures were pulled from the PMS by queries. Thin sections had asphalt thicknesses less than three inches. Mid-range sections had asphalt thicknesses of five to seven inches, and thick sections had asphalt thicknesses of more than nine inches. Aggregate base course thickness is generally eight inches, although six inches may be used on very low volume roadways. Aggregate thickness of 10 inches is common in the mountain region to avoid frost penetration into the subgrade. Performance curves, graphs of pavement condition rating versus time, were generated for each section or group of sections. A polynomial curve of form ax2 + bx + c, was fit to each curve and the time to reach a pavement condition rating (PCR) of 60 was calculated. Average, standard deviation, and histograms of the time to reach PCR of 60 was determined for each group. Time to PCR of 60 was highest for sections located in the coastal plain. The average times to PCR of 60 were 13.67, 15.2 and 14.03 years for the thin, mid-range and thick asphalt sections.
Judith B. Corley-Lay, North Carolina Department of Transportation, jlay@ncdot.gov
Jeffery Mastin, North Carolina Department of Transportation

09-1650 - Use of Structural Asset Management to Evaluate Road Substructure Drainage Systems
Session 238
Many areas in Western Canada have experienced increasing heavy commercial vehicle loadings primarily related to resource based economic development over the past three decades. Combinations of changing moisture conditions, marginal granular materials, and heavy loadings often lead to premature road structure distress and/or failure. In particular, areas with slow moving and turning truck traffic can significantly increase the applied stress states and moisture pumping effects within the road structure, both at the road surface and deep in the road structure. Structural strengthening of roads to sustain severe heavy truck loadings often requires the installation of substructure drainage systems prior to placement of the structural strengthening system. However, explicitly measuring the initial design requirements and the life cycle performance of substructure drainage systems, as well as the impact of drainage systems on structural integrity, is difficult based on traditional empirical based road structural evaluation and design methods. This study summarizes the use of a mechanistic based structural asset management approach to evaluate the performance of existing substructure drainage systems and to engineer the requirements of new drainage systems across three case studies. Based on the findings of these case studies, the use of falling weight deflection and ground penetrating radar to provide mechanistic based structural assessment measurements are effective to quantify the spatial limits of drainage systems accurately, as well as to assess the end product structural asset value and performance of in-service drainage systems.
     Curtis F. Berthelot Ph.D.,P.Eng., University of Saskatchewan, Canada, curtis.berthelot@usask.ca
     Brian  Taylor P.Eng., PSITechnologies Inc., Canada
     Erin  Stuber, PSITechnologies Inc., Canada
     Colin  Prang, University of Saskatchewan, Canada
     Brent L. Marjerison, Saskatchewan Ministry of Highways and Infrastructure, Canada
     Marty  Campbell, Red Deer County, Alberta, Canada

09-1843 - Three-Point Imaging Test for AASHTO Soil Classification
Session 474
A rapid digital image-based test has been developed for classifying highway subgrade materials by the AASHTO System. It relies on segregation of particles in a sedimentation column followed by determination of the elevations at which grains of size 2.0 mm (#10 sieve); 0.425 mm (#40 sieve); and 0.075 mm (#200 sieve) are found. Assuming that porosity variations through the column are insignificant as established in previous studies, the distances between these elevations translate to the percentages passing the various sieves. The method utilizes a previously developed calibration between an Image Wavelet Decomposition Index, CA and the Perceived Particle Diameter (PPD) in image pixel units. At a camera magnification of 32.5 pixels per millimeter, the entire grain size range from 2.0 mm to 0.075 mm is resolved. Thus, only a single fixed magnification lens is needed for the system. The paper demonstrates the accuracy of the new test through comparisons between the digital image-based results and conventional sieving for three soil specimens including a well graded sand, a uniform sine sand and a sandy silt. The advantages of the Three Point Imaging Test for AASHTO soil classification include reduced testing time, low noise, possibly lower equipment costs and elimination of airborne particles in the lab.
Roman D Hryciw, University of Michigan, romanh@umich.edu
Yongsub Jung, University of Michigan

09-3181 - Effects of Pavement Design on Frost Heave at MnROAD
Session 238
This paper presents the results of a study of the effect of different pavement design parameters on magnitude of frost heave, a major concern for pavements in cold climates. Elevations of frost pins embedded in MnROAD test sections measured over four years were analyzed, totaling to over 33,700 measurements used. Annual pin elevation changes were computed to evaluate the amount of frost heave and degree of frost heave uniformity within a cell. Statistical approaches such as visual analyses, Student-t hypothesis testing, and ANOVA analysis were used in this study to evaluate the effect of pavement design features on frost heave. The findings suggest that subgrade and base type, pavement thickness, and drainage capabilities are the major design factors that affect frost heave.
     Peter  Bly, University of Minnesota, Twin Cities
     Atika  Shamim, University of Minnesota, Twin Cities
     Lev  Khazanovich, University of Minnesota, Twin Cities, khaza001@umn.edu
     Randal  Barnes, University of Minnesota, Twin Cities
     Benjamin James Worel, Minnesota Department of Transportation

Infrastructure Preservation

09-0409 - Life-Cycle Cost Analysis of Surface Retexturing with Shotblasting as a Pavement Preservation Tool
Session 726
This paper explores the economics of replacing chip sealing and thin hot-mix asphalt overlays for highways with surface retexturing using the same shotblasting technology that is used on airport pavements. This technology is able to restores both the microtexture and macrotexture on pavements that have lost skid resistance due to polishing. An economic analysis of typical highway is conducted to determine the life cycle costs of using various options for the hypothetical project. The study utilizes the Federal Highway Administration pavement life cycle cost methodology and reports the results in Net Present Value basis to compare each skid restoration alternative. The analysis is conducted on two levels. First a traditional deterministic life cycle cost analysis is completed and it is followed by a stochastic analysis of life cycle cost using a Monte Carlo simulation. The paper concludes that shotblasting is an economically viable alternative to traditional methods for restoring lost skid resistance. It also allows the desired engineering objective to be achieved without the consumption of additional asphalt binder or aggregate thus making it an environmentally sustainable alternative as well.
Douglas D. Gransberg PE, University of Oklahoma, dgransberg@ou.edu

09-0659 - Chip Seal Maintenance: Solutions for Bleeding and Flushed Pavement Surfaces
Session 756
This report summarizes the findings of research directed at identifying maintenance solutions for bleeding and flushed pavements surfaced with a chip seal. Factors that contribute to bleeding and flushed chip seals include aggregate issues, binder issues, traffic issues, environmental issues, and construction issues. There is no better advice for dealing with bleeding and flushed chip seals than to avoid the problem from the outset by employing a preventive maintenance perspective. Bleeding is an immediate maintenance problem that must be addressed using corrective or in some cases, emergency, maintenance. The basic approaches used to treat bleeding include bridging over the liquid asphalt by applying aggregate of various types and gradations, cooling off the pavement surface by applying water with or without additives, or removing the bleeding asphalt and rebuilding the pavement seal. Flushing, in contrast to bleeding, is typically not a maintenance problem that must be addressed immediately. The basic approaches to treat flushed chip seals are to retexture the existing surface or to add a new textured surface over the flushed pavement. Three promising areas for further research and implementation relative to bleeding/flushing solutions include the use of lime water, the use of ultra high pressure water cutting, and the use of the racked-in seal at intersections.
William D. Lawson P.E., Texas Tech University, william.d.lawson@ttu.edu
Sanjaya P Senadheera, Texas Tech University

09-1857 - Georgia's Pavement Preservation with Micromilling and Thin Asphalt Overlay
Session 726
Friction courses in Georgia such as the open-graded friction course (OGFC) or Porous European Mix (PEM), have rarely been placed directly on top of a conventionally milled surface. Such placement could cause delamination of the surface layer, due to poor bonding between the friction course and the milled surface and to the likelihood of surface water being trapped in the valleys of the rough milled surface. Thus, a new layer of dense-graded surface mix would have to be placed on the milled surface before a new friction course could be placed on top of it. Use of the micromilling technique could address this problem. This paper presents the scope and findings of research that evaluated a micromilling operation in conjunction with 15.6 miles of PEM overlay on Interstate 75 south of Macon. The Georgia DOT (GDOT) Special Provision for the micromilling and PEM overlay stipulated that the micromilling operation must produce a milled surface with a ridge-to-valley depth (RVD) in the surface texture of 1.6 mm and would require corrective action when RVD exceeded 3.2 mm. The Circular Track Meter and the Ultra Light Inertia Profiler were used for measuring the macrotexture of the milled surface. Results obtained from the eight test sections indicated that the requirements were achievable and cost effective with the micromilling technology currently available. Bond strengths were also evaluated, and the results are presented herein. The estimated cost savings for the project evaluated was $58,000 per lane mile.
     James S. Lai, Georgia Institute of Technology
     Mark  Bruce, Georgia Department of Transportation
     David Mark Jared P.E., Georgia Department of Transportation, djared@dot.ga.gov
     Peter Y. Wu, Georgia Department of Transportation
     Sheila  Hines, Georgia Department of Transportation

09-2517 - Corrosion of Steel Girder Bridge Anchor Bolts
AHD45
Corrosion of anchor bolts has been revealed by inspections of steel girder bridges throughout the State of Georgia. Of Georgia’s steel girder bridges, 411 (27%) were found to be experiencing anchor bolt corrosion, with a median age of 39 years when corrosion was first reported. From field investigations of bridges built prior to 1990, A36 carbon steel anchor bolt corrosion is attributed to the formation of corrosion macrocells with the bolt’s concrete embedment and the buildup of dirt and debris at the bearing site. In bridges built post-1990, Type 304 stainless steel anchor bolts may be susceptible to galvanic coupling and localized forms of corrosion. By laboratory based experimentation, it was concluded that A36 carbon steel bearing components may experience active corrosion, with accelerated corrosion rates due to macrocell and galvanic coupling effects in an exposed pH 7.5 environment. It is noted that galvanic coupling may occur on Type 304 stainless steel anchor bolts, but further research is necessary. Type 304, 316, 2101, and 2205 stainless steels were tested for localized corrosion. Only Type 304 stainless steel exhibited localized corrosion when polarized to potentials much higher than anticipated in the Georgia bearing environment. Therefore, it may be concluded that each of the candidate alloys tested is acceptable for use as anchor bolts in Georgia. However, special consideration should be given to the use of Type 304 stainless steel in more aggressive environments, such as industrial settings or regions where deicing salts/chemicals are used frequently.
     Robert D. Moser, Georgia Institute of Technology, moser@gatech.edu
     Lisa J. Lindquist Hoeke, Georgia Institute of Technology
     Preet M. Singh, Georgia Institute of Technology
     Lawrence F. Kahn, Georgia Institute of Technology
     Kimberly E. Kurtis, Georgia Institute of Technology

09-2661 - Comparing the Methods for Evaluating Pavement Interventions: Discussion and Case Study
Session 646
Decision makers are always faced with the challenge of selecting and implementing cost-effective pavement preservation alternatives, particularly when faced with shrinking budgets and increased competition for funds. This paper reviews pavement intervention and investment evaluation criteria that have been used in past research and practice and presents a unique synthesis of pavement preservation effectiveness and efficiency evaluation techniques from both benefit and cost perspectives. The criteria are placed into the following categories: effectiveness (benefit) only, cost only, cost-effectiveness, and economic efficiency. For each criterion, the paper discusses, computational details, past applications, merits, and demerits of various evaluation criteria. Then selected criteria are computed using data from a national pavement study, and are used to evaluate alternative rigid pavement rehabilitation treatments. The case study results suggest that the superior short-term effectiveness exhibited by a treatment does not necessarily translate into superior long-term effectiveness. It was also seen that the evaluation results can vary widely among cost only, effectiveness only, and both cost and effectiveness criteria. As such, evaluation based on cost-only or effectiveness-only criteria can yield biased evaluation results. It was concluded that to be a suitable candidate, a treatment /strategy must not only be effective but must also be cost-effective and economically efficient and that the incorporation of user costs in evaluation can significantly influence the evaluation results. Such a synthesis can be a potential vital support for highway agencies in decision making for infrastructure management in general and pavement management in particular.
     Muhammad Bilal Khurshid, Purdue University, mbilal@purdue.edu
     Muhammad  Irfan, Purdue University
     Samuel  Labi, Purdue University

09-2853 - Multiperiod Bridge Investment Optimization Utilizing Pontis Results and Budget Constraints by Work Type
Session 426
One use for a bridge management system (BMS) is to optimize allocation of funds and predict future conditions given a set of funding constraints. The Virginia Department of Transportation (VDOT) uses the American Association of State Highway and Transportation Officials (AASHTO) Pontis BMS for this purpose. A critical limitation VDOT has encountered in using Pontis is that the system offers no functionality for specifying the budget by work type when performing a program simulation. This paper describes an approach developed by Cambridge Systematics for VDOT for using results generated by Pontis to optimize bridge investments over a ten-year period considering budget constraints by year for each of five work types. The approach entails performing a series of Pontis simulation runs as a one-time or occasional step, and then performing a secondary optimization with work type constraints. Two VDOT-owned systems have been developed to support the approach described here. The VDOT Pontis Robot connects to the VDOT Pontis database and performs a series of eleven Pontis simulations. Once the VDOT Pontis Robot has been run, then the VDOT Post-Pontis Optimizer can be used to optimize bridge investments for one or all VDOT districts. Performing an optimization requires approximately 5 seconds. While the approach described here leverages the Pontis BMS, it nonetheless represents a significant improvement to Pontis through implementing multi-period optimization, budget constraints by work type, and real-time generation of budget optimization results.
     William E. Robert, Cambridge Systematics, Inc., wrobert@camsys.com
     Dmitry I. Gurenich, Cambridge Systematics, Inc.
     Richard E. Thompson, Virginia Department of Transportation

Maintenance

09-0488 - Benefits of Pavement Markings: Renewed Perspective Based on Recent and Ongoing Research
Session 686
One of the most important aspects of a safe and efficient roadway is the uniform application of pavement markings to delineate the roadway path and specific traffic lanes. Pavement markings can communicate information to road users like no other traffic control device. They provide continuous information to road users related to the roadway alignment, vehicle positioning, and other important driving-related tasks. It is estimated that in the United States alone, approximately $2 billion is spent annually on pavement markings. Despite these annual expenditures, there is a general void in terms of a consolidated effort that attempts to quantify proven benefits of pavement markings. Over the years, many research projects have focused on specific elements of pavement markings. This paper was developed to bring together many of the recent and ongoing research efforts to demonstrate a renewed perspective regarding the benefits of pavement markings and, where information is available, describe the benefits of various aspects of pavement markings. This paper presents areas where conclusive findings are available, and describes areas where findings are available but show inconsistent and sometimes conflicting results.
Paul J. Carlson, Texas Transportation Institute, paul-carlson@tamu.edu

09-1216 - Computer-Aided Design of Passive Snow Control Measures
Session 538
Control of blowing and drifting snow on the nation's highways is important to reduce maintenance costs and closure times and to improve crash incidence by improving visibility, preventing drifting on the road, and reducing road icing. Means of engineered mitigation using road design and snow fences have been incorporated into a software tool, SnowMan (for Snow Management) that has been deployed for use statewide within the New York State Department of Transportation. The software has been developed as a MDL (MicroStation Development Language)application to run within the Bentley MicroStation CAD software environment used in highway design projects. The scope of SnowMan includes drift prediction (mitigated and unmitigated), evaluation of roadway cross sections and determination of trial fence solutions subject to combinations of height, setback, and porosity constraints, and prescription of upwind earthwork solutions. This paper describes the development and implementation of this software tool for mitigation of blowing and drifting snow problems and illustrates its usage, while also providing an overview of the relevant data, underlying algorithms, and engineering approaches to blowing and drifting snow mitigation as implemented in SnowMan.
     Stuart S. Chen, State University of New York, Buffalo, ciechen@eng.buffalo.edu
     Michael F. Lamanna, State University of New York, Buffalo
     Ronald D. Tabler, Tabler and Associates
     Darrell F. Kaminski, New York State Department of Transportation

09-1792 - How Drivers Perceive Visibility in Blowing Snow: Human Subject Experiments on Visibility by Viewing Videos of Blowing Snow
Session 345
Road meteorological observatories measure visibility using visibility meters. However visibility values measured by visibility meters stem from the meteorological definition, which comes from a perspective different from that of road use. Subject experiments were therefore conducted using road videos in blowing snow conditions to clarify the difference between visibility perceived by drivers and that measured using a visibility meter. The experiments revealed that the visibility perceived by drivers in blowing snow is approximately 70 meters lower than conventionally measured visibility. Also, a high correlation is observed between the visibility perceived by drivers and the sum total of projected area of snow particles passed through a unit area in a unit time. It was also learned that the visibility perceived by drivers during blowing snow is affected by the intensity of visibility fluctuation, the presence or absence of snowfall, road surface conditions, the surrounding environment (i.e. urban or suburban) and the time of day, and is hardly influenced at all by the direction of the snowstorm. Based on the above results, the need for a visibility index for road traffic in blowing snow was suggested.
     Masaru  Matsuzawa, Civil Engineering Research Institute for Cold Region, Japan, masaru@ceri.go.jp
     Hirotaka  Takechi, Civil Engineering Research Institute for Cold Region, Japan
     Yasuhiko  Kajiya P.E.Jp, Civil Engineering Research Institute of Hokkaido, Japan
     Yasuhiko  Ito, Civil Engineering Research Institute for Cold Region, Japan
     Mitsunori  Igarashi, Hokkaido Regional Development Bureau, Japan

09-1935 - State Transportation Agencies’ Implementation of Strategy to Maintain Work-Zone Mobility and Safety
Session 566
Work zone congestion mitigation strategies are utilized by transportation agencies to manage or reduce congestion through a work zone as part of the project’s Transportation Management Plan (TMP). The objective of this research is to assist agencies’ strategy selection by identifying strategies used by State Transportation Agencies (STAs) nationwide and their experiences. An online survey was developed to identify current, past, and future strategy implementation for projects similar to four developed scenarios: rural reconstruction, rural resurfacing, urban reconstruction and urban resurfacing projects. The survey received 42 responses from individuals representing 28 states (responses were received from multiple districts or regions from a few states). It was found that agencies are utilizing several strategies to address different aspects of mobility and safety. Strategy selection varied between facility location and work activity. STAs also provided strategies that failed to meet expectations and identify strategies their agency plans to implement in the future. Based on the survey results and gaps in current literature, recommendations for strategy selection and future research are provided.
Jonathan Wiegand, Federal Highway Administration, jonathan.wiegand@fhwa.dot.gov
Thomas Maze, Iowa State University

09-2043 - Nighttime Visibility of Prototype Work-Zone Markings Under Dry, Wet, and Rainy Conditions
Session 456
This study evaluated the nighttime visibility of three prototypes for an all-weather work zone pavement marking. The prototype markings included retroreflective optics that used beads with higher refractive indices in combination with conventional glass beads. This “dual-optic” system is intended to provide good visibility in both dry and wet weather conditions. The prototype marking systems were tested alongside two commercially available marking systems (one paint-and-bead system, one wet-reflective removable tape). Thirty study participants ranging in age from 55 to 80 years drove a closed-course that allowed them to view all of the marking types at night under dry conditions, in simulated rain, and on wet pavement following a simulated rain event. Participants were asked to identify the direction of work zone lane shift tapers delineated only by the markings. In the wet-recovery condition, the three prototypes and the reflective tape sustained average detection distances at 60-80% of their dry detection values, and in the continuous rainfall condition sustained average detection distances at 50-70% of dry detection values. In contrast, the average wet-recovery and continuous-rain detection distances for the conventional paint-and-bead benchmark system dropped to 28 percent and 17 percent of the dry detection distance, respectively. In addition, participants failed to detect the conventional paint-and-bead benchmark system in nearly half of the observations in the simulated rain condition.
     Laura  Higgins, Texas Transportation Institute, l-higgins@tamu.edu
     Jeffrey David Miles E.I.T., Texas Transportation Institute
     Paul J. Carlson, Texas Transportation Institute
     David M. Burns, 3M Company
     Fuat  Aktan, 3M Company

09-2540 - Pavement Marking Application: Bead Gun Evaluation Study Using a High-Speed Camera
Session 686
The Iowa Department of Transportation (DOT) relies heavily on the performance of waterborne pavement markings in providing guidance to motorists. Waterborne markings are installed by DOT crews at the district level and cover roughly 95 percent of the state maintained system. The DOT is continually seeking opportunities to improve crew-applied waterborne marking performance in terms of durability and retroreflectivity. Specific to night-time performance, proper placement of the glass beads, within the waterborne paint, is critical to maximizing retroreflectivity (visibility back to the driver). One of the ways the DOT improved retroreflectivity was to improve bead placement through slowing their trucks down from around 14 mph down to 8 mph. With a limited painting season, and slower truck speeds, the DOT found it difficult to achieve their desired annual paint coverage. In an effort to increase application speed and yet achieve good bead placement (and resulting retroreflectivity) the DOT investigated the option of using a new style of bead gun. This paper presents the findings of a field study using two different (higher application speed) bead guns and reports on the contrast between the two devices in terms of bead delivery versus application speed.
     Omar  Smadi, Iowa State University, smadi@iastate.edu
     Craig  Mizera, Snyder and Associates, Inc.
     Neal R. Hawkins, Iowa State University
     William  Zitterich, Iowa Department of Transportation

09-3451 - The Bioimprovement (Vegetation) of Soils for Highway Applications Using RECPs
AHD50
Highway departments are regularly faced with minimizing soil erosion from highway construction sites. One of the most effective ways of minimizing soil erosion is to provide ground cover that can intercept raindrops. Although vegetation is commonly used, it is difficult to establish on steep slopes and in high flow areas and to a suitable density to provide adequate ground coverage. As a result, rolled erosion control products (RECPs) are often used to provide immediate ground cover protection for soils, enhance the growth of vegetation, and reinforce vegetation once it is established. The success of RECPs has led to the development of a wide variety of different RECPs that can vary significantly in basic properties and performance. Although many studies have been published documenting the successful use of RECPs, limited work has been done to compare the rainsplash erosion performance of different types of vegetated RECPs and the mechanisms of how they work to minimize soil erosion. Based on the results of more than 200 laboratory rainsplash erosion tests on 13 different types of vegetated RECPs, it was found that the use of vegetated RECPs can significantly reduce soil losses on bare soil slopes by an average of 95% to 100% in comparison to bare soil alone. Vegetation improved the performance of the RECPs alone by an average of 54% and 95%. Care must be taken in the design and selection of RECPs to optimize their performance.
Jennifer Lynn Smith, SUNY Environmental Science & Forestry, jsmith@esf.edu
Shobha K. Bhatia, Syracuse University

Operations

Pavement Management

09-0228 - Effects of Heavy Truck Operations on Repair Costs of Low-Volume Highways
Session 342
The economic impact of overweight permitted vehicles hauling sugar cane on Louisiana highways is evaluated. The highway routes that are used to haul this commodity are identified and statistical samples are selected and analyzed. Two different vehicle types and three different gross vehicle weights are chosen including 100,000-lb. and 120,000-lb. AASHTO design guidelines are used to determine the effects of heavy loads on pavements and bridges. The approach requires the overlay thickness needed to carry traffic from each gross vehicle weight for the design period and costs based on 20-year period. The state bridges are evaluated to satisfy regulations for the loading requirements and a fatigue cost is estimated for each safe crossing of a bridge. Results indicate that the damage from each FHWA Type 9, with a gross vehicle weight of 100,000-lb sugar cane load, to pavement and the bridge fatigue cost is at bout $5,500/year. Therefore, the current sugar cane trucks permit fee of $100 per vehicle per year is not adequate to recover these costs. It is recommended that the current 100,000-lb. gross vehicle weights be maintained, but the permit fees are increased, or the vehicle type is changed from a FHWA-Type-9 to a Type-10 vehicle. Under the second alternative, the permit fee can be reduced to zero and a tax incentive of $683 can be given to each truck for the conversion. Also, it is necessary to increase the highway funds to handle the extra damage caused by the increase of truck load limits.
     Aziz  Saber, Louisiana Tech University, saber@latech.edu
     Mark J. Morvant, Louisiana Department of Transportation and Development
     Zhongjie  Zhang, Louisiana Department of Transportation and Development

09-0955 - Full-Scale Experiment on Foam Bitumen Pavements in CAPTIF Accelerated Testing Facility
Session 300
Foam bitumen stabilization is a viable alternative to reduce aggregate consumption in New Zealand. An accelerated full-scale experiment on foam bitumen pavements was conducted in the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF), as part of a Transit New Zealand research project to study the effects of foam bitumen on unbound granular materials. Six pavement sections were tested. Three were constructed using foam bitumen contents of 1.2%, 1.4% and 2.8% respectively, plus a common active filler content of 1.0% cement. Two more pavements were constructed adding cement only (1.0%), and foam bitumen only (2.2%). In addition, one control section with the untreated unbound material was tested. Strains were collected using a 3D Emu soil strain system installed in each pavement section. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs), the sections stabilized with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilized with foam bitumen and 1.0% cement. Water was introduced into these three pavements plus additional accelerated loading, and caused the section with the lowest foam bitumen content to fail. These results showed that foam bitumen and cement had a significant effect on improving the performance of the materials studied. Material samples taken for Indirect Tensile Strength (ITS) and Repeat Load Triaxial (RLT) for laboratory tests showed that the ITS test was a good predictor of the pavement performance giving a clear trend, while RLT results were not conclusive.
     Alvaro  Gonzalez, University of Canterbury, New Zealand, ago30@student.canterbury.ac.nz
     Misko  Cubrinovski, University of Canterbury, New Zealand
     Bryan Dale Pidwerbesky, Fulton Hogan Ltd., New Zealand
     David  Alabaster, New Zealand Transport Agency

09-1574 - Matric Suction Prediction Model Used in New AASHTO Mechanistic-Empirical Pavement Design Guide
Session 386
Equilibrium moisture beneath highway pavements is critical to pavement design because it directly affects the strength and stiffness of pavement systems. Moisture is related to soil suction by means of the soil-water characteristic curve (SWCC). Previous research has indicated a correlation of suction with Thornthwaite Moisture Index (TMI) and soil type; however, these suction correlations exhibit large variability. Under the National Cooperative Highway Research Program (NCHRP) project 9-23 sponsored by the Federal Highway Administration (FHWA), soil samples were collected from beneath thirty pavement sections throughout the United States. SWCCs and index properties were measured on collected samples at Arizona State University. The in-situ degree of saturation was obtained and the corresponding in-situ soil suction was found from measured SWCCs. Based on the field and laboratory data, two models were developed to predict equilibrium suction under pavements: one model suitable to granular non-plastic materials and another model suitable to fine-grained plastic materials. These models were adopted in the new AASHTO Mechanistic Empirical Pavement Design Guide (ME-PDG) as they exhibited good results with variability within acceptable limits. The development of the models is presented in this paper.
     Claudia E. Zapata, Arizona State University, czapata@asu.edu
     Yugantha Yasanayake Perera, Maricopa County Department of Transportation
     William N. Houston, Arizona State University

09-1622 - Impact of Agribusiness on South Dakota’s Local Roads: Successes and Failures
Session 342
Local roads are being destroyed by rapid growth in agribusiness. This paper will showcase successes and failures of local roads impacted by the construction of new agriculture related businesses. The paper will also illustrate how local agencies are handling the new wave of heavy trucks traveling over local roads at a rate that had never been experienced in the past. Some of these roads have been serving local traffic for over 40 years without major breakdown. But since the construction of new agriculture related plants and businesses these roads deteriorate at an alarming rate. The problem is compounded by lack of any improvement strategy by either the local government that owns the road or the owner of the new plant. Two success stories and one failure will be discussed in the body of this paper. The success is attributed to the foresight of the local officials who knew the magnitude of the new generated traffic and took the necessary steps to strengthen the road structure. The one failure was the result of lack of planning and funds needed to meet the new challenge. Local agencies should be very cautious in accepting a new agribusiness before exploring the negative consequences that will definitely impact the integrity of the local road system.
     Ali A. Selim, South Dakota State University, ali.selim@sdstate.edu
     Ken  Skorseth, South Dakota State University
     Hesham  Mahgoub, South Dakota State University

09-1710 - Prediction of Flexible Pavement Remaining Strength and Overlay Design Thickness Using Stochastic Modeling
Session 401
The future pavement remaining strength is predicted from initial pavement strength using layer structural capacity adjustment factors. The initial pavement strength is defined as the total structural capacity associated with the asphalt concrete and underlying granular layers estimated using appropriate relative strength indicators such as the Gravel Equivalent (GE) or Structural Number (SN). The future pavement remaining strength is estimated as the product sum of multiplying the initial layer strength by the corresponding adjustment factor. The structural adjustment factor represents the percentage of remaining strength for a particular pavement layer at a specified service time (t). The structural capacity adjustment factor associated with the asphalt layer is the principal factor estimated from a project performance curve generated using stochastic modeling. The discrete-time Markov model is used to predict pavement distress ratings for a particular project over a specified service life (T). A simplified approach is presented for estimating a project transition matrix using only initial and terminal transition probabilities. The predicted distress ratings are used to construct a project performance curve. The area falling under the performance curve has long been recognized as a direct measure of the pavement relative strength. Therefore, the principal structural capacity adjustment factor is defined as the ratio of the area under the performance curve for the remaining service period (T-t) and the area under the entire performance curve for a service life (T). A sample application is provided with results used to generate empirical models to be used in developing rehabilitation strategies and management policies at the network level.
Khaled A. Abaza, Birzeit University, Palestine, kabaza@birzeit.edu
Maher M. Murad, University of Pittsburgh, Johnstown

09-1737 - Lessons Learned from MnROAD (1992–2007: Whitetopping Design, Construction, Performance, and Rehabilitation
Session 654
The design, construction, performance and rehabilitation of ten whitetopping (concrete overlay of asphalt) test cells at the Minnesota Road Research Project (MnROAD) are described and discussed. These test cells can be considered to constitute an accelerated loading test because the concrete thicknesses represent low-volume road applications, but they are subjected to Interstate traffic (with high volumes of heavy truck traffic). In many of the lower volume road applications for which these designs would typically be employed, it would take more than 50 years to accumulate the same number of heavy vehicle loads actually carried by the MnROAD whitetopping cells, many of which are still in serviceable condition. The performance of the original whitetopping test cells at the MnROAD project appears to be related to traffic volume, wheel load placement and layer bonding, particularly for the 3-in and 4-in [75-mm and 100-mm] test sections. Observed good performance can be attributed to good support by (and bond with) the underlying asphalt layers. Poor performance was observed where longitudinal joints were placed in or near the wheel paths. The rate of reflective cracking is also affected by traffic levels, with more rapid development in the driving lanes than in the passing lanes. The incidence of reflection cracking appears to depend on the relative stiffnesses of the concrete and asphalt layers (taking environmental effects on asphalt stiffness into consideration). Recommended “best practices” for whitetopping repair were developed at MnROAD. These practices focus on achieving good bond, avoiding reflective cracks and providing good curing.
Mark B. Snyder, University of Pittsburgh, mbsnyder@concretepavements.org

09-1870 - Practical Approach to Measuring and Reporting Friction and Macrotexture at Variable Test Speeds
Session 579
Due to safety concerns associated with friction testing on both high and low-speed facilities, testing at variable speeds has been investigated by the Florida Department of Transportation (DOT) and others. Previous research has demonstrated that reasonable correlations may be developed between friction test data obtained at the standard test speed of 40 mph (64.4 km/h) and other speeds. As part of an effort to harmonize its fleet of full-scale, locked-wheel skid testing equipment with portable reference test equipment as described in ASTM E 1960, the Florida DOT also evaluated the skid number speed Gradient (Gv) for use in transforming friction and macro-texture measurements obtained at variable highway speeds. This paper documents the results of this evaluation. Based on the results of this study, a practical method of measuring pavement friction and macro-texture at variable highway speeds with the Florida DOT locked-wheel test unit and the ribbed tire is presented. Since the results of the ribbed tire test are known to be significantly influenced by pavement micro-texture, and the Mean Profile Depth (MPD), as measured with the high-speed laser is a direct measure of macro-texture, FN40R and the complementary MPD data together may be readily employed to characterize the frictional properties of the pavement. This approach builds on Florida’s historical database of locked-wheel, ribbed-tire test data, while adding a direct measure of macro-texture and the flexibility of testing at variable speeds. Practical implementation recommendations and examples are provided.
     N. Mike Jackson, University of North Florida, njackson@unf.edu
     Bouzid  Choubane, Florida Department of Transportation
     Charles R. Holzschuher III, Florida Department of Transportation

09-1943 - Backcalculated and Laboratory Measured Resilient Modulus Values
Session 401
The resilient modulus (MR) of roadbed soils is a necessary parameter in pavement design. The MR of roadbed soils is dependent on the soil type, water content, dry density, particle gradation, Atterberg limits, and stress states. Several procedures can be used for the determination of the; laboratory testing, backcalculation using nondestructive deflection test (NDT) data, and correlations to other soil parameters such as CBR, density, and water content. The first procedure is time consuming, expensive and requires substantial resources to cover the various roadbed soils under the road network. The second is relatively in-expensive, fast and can be designed to cover representative soils under the pavement network. The third procedure is approximate and may be used for the level-2 design of the Mechanistic-Empirical Pavement Design Guide (M-EPDG). The Michigan Department of Transportation (MDOT) sponsored a research project for the development of a systematic procedure to determine the MR values for all soil types encountered under the pavement network in the State of Michigan. The procedure includes laboratory testing of representative disturbed and undisturbed soil samples, NDT using the MDOT Falling Weight Deflectometer, and developing correlations between the MR values obtained from the two tests and between the MR values and other soil parameters that can be obtained using simple tests. The developed correlation equations between the MR measured values and the other soil parameters are presented elsewhere (1), whereas the correlations between the laboratory obtained and the backcalculated MR values are discussed in this paper.
     Tyler A. Dawson, Michigan State University
     Gilbert Y. Baladi, Michigan State University, baladi@egr.msu.edu
     Colin P. Sessions, NTH Consultants, Ltd.
     Syed Waqar Haider P.E., Michigan State University

09-2031 - Development of Spring Load Restrictions on County Roads: Rio Blanco County Experience
Session 342
Rio Blanco County is located in the rural northwestern corner of the State of Colorado. Recently, there has been a significant increase in the truck traffic on the county roads, due to increased oil and gas exploration activities. The presence of such heavy trucks has raised concerns about the impact of additional truckloads on the pavement conditions of the county roads, particularly due to the seasonal variation in the subgrade soil conditions as a result of temperature variation. A study was initiated to develop short term Spring Load Restrictions (SLR) guidelines for Rio Blanco County for the spring 2007. This study was based on deflection testing and was successfully completed by late spring 2007. The results from this study were further validated using data collected from sub-surface instrumentation used as part of the on-going Phase 2 of the study to develop long term SLR guidelines for the County. In spring 2007, the start of the SLR was estimated using a combination of deflection testing and Thawing Index (TI) model. In this approach, the TI model from Minnesota DOT was adopted to define the expected time frame of the start of the spring thawing. Deflection testing was then performed during this time to examine the actual decrease in strength of the pavement structure and thus define the appropriate start of the SLR on the County roads. The end of the SLR was estimated again based on deflection testing to monitor the pavement condition. The deflection data collected during this project showed that the subgrade soils in the study are susceptible to a reduction in structural strength during the spring thaw season. Additional deflection testing cycles were completed to determine when the pavement regained its strength. Validation data from the sub-surface instrumentation showed that the TI model might be acceptable to define the start of the SLR based on the forecasted weather conditions, while monitoring moisture content exclusively might not be adequate for determining when SLR can be lifted unless more historical data exists for comparison. In this paper, the development the short term SLR policies for spring 2007 for Rio Blanco County is presented, together with the validation of the results of this study using data collected during spring 2008.
     Wael  Bekheet, Alexandria University, Egypt, wbekheet@gmail.com
     Harry  Sturm, Stantec Inc
     Dave  Morlan, Rio Blanco County

09-2044 - Posttraffic Testing to Study Failure Mechanisms of Rubblized Concrete Pavements with Hot-Mix Asphalt Overlays
Session 300
Full-scale traffic tests were completed on three rubblized rigid airport pavements which had been overlaid with five inches (12.7 cm) of hot mix asphalt at the FAA’s National Airport Pavement Test Facility. Initially, the overlaid pavements were trafficked with a 4-wheel landing gear configuration (with wander) and 55,000-lbs (25-tonnes) wheel load. Straightedge rut depth measurements and transverse profile measurements were made at regular intervals during the traffic tests. No significant distresses were observed during the 5,000 passes, after which the wheel load was increased to 65,000-lbs (29.5-tonnes) and a 6-wheel landing gear was used for testing. One of the rubblized pavements (MRC – rubblized concrete on conventional base) exhibited complete structural failure. MRG (rubblized concrete on grade) was considered to have suffered severe structural deterioration at the end of trafficking but retained sufficient structural capacity to support the applied load. MRS (rubblized concrete over econocrete base) did not exhibit severe structural deterioration at the end of trafficking despite having accumulated significant levels of rutting and shear flow in the asphalt. Four trenches were opened perpendicular to the centerline of the test items to conduct posttraffic investigation into the failure mechanism of the pavement structure. The trenching included testing for layer characterization and removal of each of the pavement layers to reveal the subgrade interface and subsequent subgrade layers below. Tests conducted on the pavement component layers included plate load tests, CBR tests, in-situ densities, moisture contents, layer profile measurements, and visual evaluations. This paper summarizes the results from posttraffic tests. The performance of MRS under a 65,000-lb (29.5-tonnes) wheel load suggests that rubblized concrete pavements with HMA overlay are a viable option on commercial airports because a stabilized base underneath the rubblized concrete layer limits the vertical deflection in the layer below the rubblized concrete layer and helps in keeping the rubblized pieces tightly interlocked. The results from posttraffic tests were useful in providing some insight into the failure mechanism of rubblized concrete pavements.
     Navneet  Garg, FAA William J. Hughes Technical Center, navneet.garg@faa.gov
     Gordon F. Hayhoe, Federal Aviation Administration
     Lia  Ricalde, SRA International, Inc.

09-2063 - Field Performance of Stabilized Blended Calcium Sulfate Materials Under Accelerated Pavement Testing
Session 300
BCS represents Blended Calcium Sulfate, a recycled fluorogypsum mixture that has been used in Louisiana as a pavement base layer for more than a decade. Without further chemical stabilization, the major concern of using raw BCS as a pavement structural layer is its moisture susceptibility. It could cause both short-term construction difficulties and long-term performance problems. In order to verify the efficiency of BCS stabilization schemes that was obtained from laboratory results and further assess the field performance of stabilized BCS materials as well as related cost benefits, three accelerated pavement test sections including two of different stabilized BCS bases and one of a crushed stone base were recently tested at the Louisiana Pavement Research Facility (PRF) in Port Allen, LA. The three sections shared a common pavement structure. The only difference was the base course materials. Each test section was instrumented with one multi-depth deflectometer and two pressure cells for measuring related pavement responses. Surface distress survey and the falling weight deflectometer (FWD) tests were performed at the end of every 25,000 load repetitions. The overall accelerated loading results indicated that a test section containing the GGBFS stabilized BCS base outperformed other two sections by a significantly large margin. FWD backcalculation results indicated that the GGBFS stabilized BCS base generally possessed an in situ modulus value higher than that for an asphalt concrete layer and performed like a lean concrete. Cost benefit analysis results further indicated that when using the GGBFS stabilized BCS in lieu of a stone base in a flexible pavement design, the asphalt concrete thickness could be readily reduced and thus the construction costs might be saved immediately.
     Zhong  Wu, Louisiana State University, zhongwu@ltrc.lsu.edu
     Xingwei  Chen, Louisiana Transportation Research Center
     Louay N. Mohammad, Louisiana State University
     Zhongjie  Zhang, Louisiana Department of Transportation and Development

09-2121 - Estimation of Truck Traffic Inputs for Mechanistic-Empirical Pavement Design in California
Session 574
This paper developed default truck traffic inputs for mechanistic-empirical (ME) pavement design procedures for the California highway system based on California weigh-in-motion (WIM) data. Both cluster analysis and regression analysis were applied to develop the default axle-load spectra. Regression analysis produced unsatisfactory results so it was not used. On the basis of cluster analysis of axle-load spectra, the WIM sites were divided into several groups, and default truck traffic inputs were estimated for each group. A decision tree was developed to aid designers in selecting the appropriate default factors based on easily available information: geographic location and traffic volume and composition. These data can be obtained from the California Department of Transportation (Caltrans) annual report of average annual daily truck traffic (AADTT). Traffic inputs were developed for both the Caltrans Mechanistic-Empirical Pavement Design (CalME) and the National Cooperative Highway Research Program (NCHRP) Mechanistic-Empirical Pavement Design Guide (MEPDG) software.
     Qing  Lu, University of California Pavement Research Center, qlu@ucdavis.edu
     Yu  Zhang, University of South Florida
     John  Harvey, University of California, Davis

09-2132 - Calibration of the Flexible Pavement Portion of the Mechanistic-Empirical Pavement Design Guide for the Washington State Department of Transportation
Session 616
The Mechanistic-Empirical Pavement Design Guide (MEPDG) is proposed as an advanced pavement design tool which integrates up-to-date pavement practices. Since the release of the MEPDG in 2004, the Washington State Department of Transportation (WSDOT) has been continuously working on calibration and evaluating the program with regard to implementation for state and local agencies. This paper presents WSDOT’s latest efforts on the calibration of the flexible pavement portion of the MEPDG against the data obtained from the Washington State Pavement Management System (WSPMS). It first describes the preparation process of the required input data. Detailed descriptions of input values are provided, since they may be generally applicable to states with similar conditions. The calibration process is described and followed by a discussion of results and potential implications. Emphasis is placed on major observations and general issues encountered in the calibration process. An implementation plan is being prepared to potentially replace the current AASHTO 1993 Design Guide with the MEPDG in Washington State. This study provides valuable conclusions for national applications: (1) the flexible pavement distress models were calibrated successfully; (2) WSDOT flexible pavements require local calibration differently from the defaults; and (3) A software bug does not allow calibration of the roughness model. Results indicate that, with a few improvements, MEPDG software can be used as an advanced tool to design flexible pavements and predict future pavement performance.
     Jianhua  Li, Washington State Department of Transportation, lijia@wsdot.wa.gov
     Linda M. Pierce, Applied Pavement Technology, Inc.
     Jeffrey S. Uhlmeyer, Washington State Department of Transportation

09-2297 - Methodology for Assessing Heavy Traffic Impacts on Gravel Roads
Session 342
The Wyoming Technology Transfer Center in cooperation with the Wyoming Department of Transportation and Sheridan, Johnson, and Carbon Counties undertook a three-year pilot asset management program. These counties were selected because of the significant impacts to their road networks arising from oil and natural gas drilling activities. One objective of this program was to assess the impacts to the counties’ roads from drilling activities. This paper describes this assessment. Based on surface conditions, improvement recommendations were made for roads with inadequate surface conditions for their functional class. The cost of these recommended improvements was examined for both the roads serving predominantly drilling activities and for the rest of the counties’ roads, along with the distresses driving these recommendations. By comparing the rate at which improvements were recommended on the drilling and non-drilling roads, conclusions about the impacts of drilling traffic are drawn. The portion of drilling roads in sub-standard condition for their functional class is much higher than that for the other county roads. The greatest impact in terms of the cost of improving these roads to adequate ride conditions is on the Collector roads, with lesser impacts to Local roads. It is clearly demonstrated that heavy traffic associated with drilling activities has done significant damage to these three counties’ roads, above and beyond what would be anticipated from typical traffic loads. The methodology presented here could easily be adapted to other road systems experiencing a significant influx of heavy truck traffic to assess the additional traffic’s impact.
George Huntington PE, University of Wyoming, georgeh@uwyo.edu
Khaled Ksaibati, University of Wyoming

09-3199 - Evaluating The Utility Of Existing Pavement Management System State Deflection Data For Use In The Implementation Of The Me-pdg For Arizona
Session 401
The modulus backcalculation from Falling Weight Deflectometers is one of the primary means for evaluating in-situ resilient properties of pavement materials. When evaluating material moduli from the same location by using deflection data from different sources, it is highly probable that different methodologies will lead to differing results. This study presents a comparative analysis of backcalculated moduli results performed to quantify the differences between the historic Arizona Department of Transportation - Pavement Management System (ADOT-PMS) and the Strategic Highway Research Program – Long Term Pavement Performance (SHRP-LTPP) databases. Pavement sections were selected from numerous SHRP sites in Arizona, having both forms of deflection data available at the same location and in the same general time frame. The results of this study indicated that there was a poor correspondence between backcalculated layer moduli from both databases. As a general rule, the degree of layer correspondence improved as layer depths gradually increased (subgrade was the most accurate comparison). On the other hand, fairly good correspondence was obtained for all moduli between two differing backcalculation schemes (MODCOMP v4.2 and MODULUS v6.0). Finally, it was found that the use of the simple, closed form solution to estimate subgrade moduli from the outer geophones, gave comparable answers to the more complex backcalculated solutions based upon total deflection basin results. This gives rise to the possibility that significant reductions in cost and labor can be achieved in maintaining PMS systems and by utilizing the outer geophone equation as an implementation approach for the ME-PDG.
Carlos Cary, Arizona State University
Claudia E. Zapata, Arizona State University, czapata@asu.edu

09-3614 - Effect of Suction on Resilient Modulus of Compacted Fine-Grained Subgrade Soils
Session 690
The resilient modulus of compacted subgrade soils is the primary mechanical property required in the mechanistic-empirical design of pavement structures. In most cases, the resilient modulus is determined on a specimen prepared at a single compaction condition (i.e., near optimum water content and at a specified percentage of the maximum dry unit weight). However, in the field, the resilient modulus changes in response to changes in moisture content and corresponding changes in matric suction. This paper describes the relationship between resilient modulus and suction for four fine-grained compacted subgrade soils. Resilient modulus testing was conducted in accordance with NCHRP 1-28A on test specimens prepared from each soil that were conditioned to different matric suctions. Summary resilient modulus increases with increasing matric suction. This relationship is quantified empirically using a modulus ratio defined as the ratio of the summary resilient modulus at a particular suction to a reference summary resilient modulus. Two reference summary moduli were considered: (i) the modulus at optimum compaction conditions and (ii) the modulus at saturation. The modulus ratio is linearly related to the logarithm of matric suction for all soils.
     Auckpath  Sawangsuriya, Thailand Department of Highways
     Tuncer B. Edil P.E., University of Wisconsin, Madison, edil@engr.wisc.edu
     Craig H. Benson PhD, PE, University of Wisconsin, Madison

09-3744 - Construction and Performance of Georgia’s Permeable Surface Mixes on 2006 NCAT Pavement Test Track
Session 300
The Pavement Test Track is a full-scale, accelerated performance test facility for flexible pavements managed by the National Center for Asphalt Technology (NCAT) at Auburn University. Forty-six unique 60 meter test sections are installed around a 2.8 kilometer oval and subjected to accelerated damage via a fleet of tractors pulling heavy triple trailers. Methods and materials that produce better performance for research sponsors are identified so that future pavements can be selected based on objective life cycle comparisons. Using three sections built for the third cycle of testing, NCAT was asked by the research sponsor to compare the construction and performance of permeable surface mixes containing two different aggregate sources that were placed with conventional and dual layer paving equipment. All three sections were placed on perpetual foundations to ensure that distresses would be isolated to the experimental surface mixes. Two sections were placed with a conventional single layer paver, one containing cubical aggregates and the other containing more flat and elongated aggregates. The third section was built using the same slightly flat and elongated aggregates; however, the surface consisted of a thin 9.5 mm drainable mix over a thicker 12.5 mm drainable mix. By using an imported dual layer paver of European design, it was possible to place both drainable mixes simultaneously without applying an intermediate tack. The purpose of the 9.5 mm upper mix is to prevent debris from clogging the void structure of the lower 12.5 mm mix, which would have a negative impact on drainability performance. A competitive bidding process was used to select the contractor that produced all the mixes and also paved the two conventional single layer sections. A German crew was provided by the equipment supplier to operate the imported paver and place the drainable mixes on the dual layer section. All laboratory and field construction quality data generally met the expectations of the research sponsor. Laboratory permeability and bond strength testing were run on samples cored form the surface of the Track. Natural rainfall events were used to subjectively assess the drainability performance of each section during actual fleet operations. The section built with slightly flat and elongated aggregates appeared to exhibit more effective drainability than the section built with the more cubical aggregates, and the dual layer pavement appeared to exhibit more effective drainability than the conventional single layer drainable surface.
Raymond Lee Powell, National Center for Asphalt Technology, buzz@auburn.edu

Safety

Soil Mechanics

09-1034 - AASHTO Load and Resistance Factor Design Axial Design of Driven Pile at Strength Limit State
Session 203
This paper describes the axial compression design of a single-driven pile at the strength limit in accordance with AASHTO LRFD Design Specifications (2007). This paper was prepared to help State departments of transportation (DOTs) with interpretation and proper integration of AASHTO’s LRFD design specifications for driven piles into their design and construction practice. The values needed for a single pile design are: a) for a friction or end-bearing pile, the maximum factored axial structural load that can be applied to top of the pile, and b) for a friction pile the maximum pile penetration length a pile can be driven to without damage, and the required pile length for a given factored axial load, Qf. The calculations of these values are demonstrated using AASHTO static analysis methods, field methods (including those that consider and verify setup), and the wave equation analysis. The LRFD design procedure is demonstrated for two common driven pile types: H-Piles and Cast-in-place (CIP) pipe piles. A properly implemented AASHTO geotechnical LRFD specification would allow for higher pile design loads and shorter pile length than commonly employed in the traditional ASD practices. Recommendations for the development of accurate and economical local geotechnical design methods are furnished.
     Naser Mahmood Abu-Hejleh P.E., Federal Highway Administration, Naser.Abu-Hejleh@fhwa.dot.gov
     Jerry  Dimaggio, Transportation Research Board
     William Kramer,  Kramer, Illinois Department of Transportation

09-1910 - Capacities and Deflections of Laterally Loaded Shafts behind an MSE Wall
Session 459
Current practice for designing laterally loaded shafts that pass through a mechanically stabilized earth (MSE) wall often involves isolating the shaft from the MSE mass and anchoring the shaft into rock with a rock socket. Sizeable cost and time savings could be realized, while still maintaining performance and reliability, if a method were available to evaluate the lateral load capacity of a shaft that is supported by the MSE mass alone with no rock socket. To provide information to develop such design methods, the construction, instrumentation, and loading of multiple 36 in. (0.914m) diameter shafts supported within the reinforced mass of a 20 ft (6m) tall MSE block wall designed using existing FWHA procedures without consideration of lateral loads was conducted for the Kansas Department of Transportation (KDOT). This paper describes the design and construction of the wall and the shafts, which were designed as drilled shafts, and the results from the lateral load tests of four shafts. These shafts had lengths that were equal to the full height of the wall and had spacings from the back of the wall facing to the center of each shaft of 1, 2, 3, and 4 shaft diameters. Results for both load and displacement of the shafts, the width of shaft influence, and the relative displacements of the shafts and the wall facing during loading are presented, along with design recommendations.
     Matthew  Pierson, University of Kansas
     Robert L. Parsons, University of Kansas, rparsons@ku.edu
     Jie  Han, University of Kansas
     James Joseph Brennan, Kansas Department of Transportation

09-2118 - In-place Microelectromechanical System Inclinometer Strings: Evaluation of an Evolving Technology
Session 453
Continuous monitoring of subsurface ground movements is accomplished with in-place instruments utilizing automated data acquisition methods. These typically include TDR (Time Domain Reflectometry) or assemblies of several servo-accelerometer-based, electrolytic level transducer-based, or MEMS (Micro-Electro-Mechanical Systems) -accelerometer-based inclinometer probes that are usually aligned within grooved inclinometer casing. In-place inclinometers can determine the magnitude and direction of ground deformation, whereas TDR is primarily used to identify depths of active shearing only. Because the number of sensors in an in-place inclinometer chain may be somewhat limited due to cost or technological constraints, installation of in-place inclinometers on landslides has typically been preceded by the use of TDR or traversing probe inclinometers to target zones of interest. The New York State Department of Transportation (NYSDOT) is participating in prototype installations to evaluate long MEMS-inclinometer strings that do not utilize grooved casing or guide wheels. The new, guideless device and installation method is being used to achieve detailed deformation profiling (at 1-ft (0.3m) increments) to detect multiple zones of ground deformation. This approach can survive very large ground deformations and continue to collect measurements, and is able to be retrieved from severely distorted casing and redeployed. There are however, significant trade-offs and drawbacks associated with this guideless approach, notably concerning questionable backfill support and misalignment of sensors. This paper describes the prototype applications and issues that NYSDOT has experienced on two projects and makes suggestions for future improvements.
Matthew Brian Barendse P.E., New York State Department of Transportation, mbarendse@dot.state.ny.us
George Machan, Landslide Technology

09-2198 - Evaluation of High-Capacity Composite Spun Piles
Session 203
Traits of two broad categories of deep foundations - replacement and displacement piles are best combined by a newly introduced composite spun pile. This composite spun pile is constructed by deep mixing first and inserting a precast prestressed spun concrete pile into the deep mixed column. The spun pile is then driven into an end-bearing layer to meet the criterion of end resistance. The pile utilizes a larger peripheral area of soil cement mix to transfer load to its surrounding ground, at the same time it utilizes higher stiffness of the spun pile to minimize an axial compression. The piling operation is relatively quiet, minimizes spoil problems, and facilitates better quality control. A pile design principle for the composite pile is presented and the performance of this new pile system is verified by five instrumented field full-scale pile load tests. Improvement on shaft resistance was observed as depicted by the correlation between standard penetration test (SPT) N values of the surrounding soil and the measured skin friction along the pile. The contribution of the measured toe resistance over the total applied load varied from 2.3 to 36.7% depending upon the geotechnical properties of foundation layers. The field tests clearly showed that composite spun piles have high capacities and can be used as a reliable alternative to traditional driven as well as bored piles in the current practice.
Anil Bhandari, University of Kansas, banil@ku.edu
Jie Han, University of Kansas

09-2255 - Dynamic p-y Backbone Curves from 1-g Shaking Table Tests
Session 459
The p-y curve method, which can account for the non linear behavior of soil, is used for modeling dynamically loaded pile foundations in pseudo-static analysis. The p-y curves for static loading conditions are frequently applied even for seismic loading conditions by slight modifications without any further verification, because dynamic p-y curves for seismic loading conditions have not been well established. In this study a series of 1g shaking table tests were carried out in various conditions of acceleration frequency, acceleration amplitude for an input load, flexural stiffness of a pile shaft and a surcharge load at the pile head. The experimental p-y curves for each test condition were evaluated, from which dynamic p-y backbone curves are produced. As a result, two limit backbone curves, due to the big scatter of the test data, were specified as lines connecting the boundary peak points of the experimental p-y curves. In order to represent the upper and lower limit backbone curves numerically, empirical equations were developed for the initial stiffness and the ultimate capacity of soils as a function of a friction angle and a confining stress. The applicability of dynamic p-y backbone curves suggested in this study was evaluated based on the test results of other researchers cited in literature. Also, the backbone curves were compared with the p-y curves that are currently used in practice.
     Eui Kyu  Yang, Seoul National University, South Korea
     Sangseom  Jeong, Yonsei University, South Korea
     Jeong Hwan  Kim, Samsung Corporation, South Korea
     Myoung Mo  Kim, Seoul National University, South Korea, geotech@snu.ac.kr

09-2745 - Review of Mechanically Stabilized Earth Wall Performance Issues
Session 459
For approximately 35 years, Mechanically Stabilized Earth (MSE) walls have become increasingly popular in the development of transportation and other projects. The first U.S. MSE wall was constructed in California in the early 70’s. Since that time MSE walls have become generally accepted as a standard wall type on America’s Highways. MSE walls regularly reach heights in excess of 12-meters and can be technically and economically feasible to heights in excess of 30-meters. Very few MSE walls fail completely, but there are many walls which haven’t performed as well as intended. In order to address this issue, several transportation departments have completed or are in the process of reviewing their design and construction practices in order to improve the overall performance of their MSE walls. Ten typical problems identified by these reviews are related to geometry and wall layout, obstructions, wall embedment, surface drainage, contractor experience, claims, backfill placement and compaction, panel joints, leveling pad, durability of facing. Furthermore, asset management techniques are recommended as a tool to help optimally manage and maintain MSE and other wall types.
Daniel Enrique Alzamora P.E., Federal Highway Administration, daniel.alzamora@fhwa.dot.gov
Scott A. Anderson, Federal Highway Administration

09-2981 - NCDOT’s Practice and Experience with Design-Build Contract: Geotechnical Perspective
Session 203
This paper presents the North Carolina Department of Transportation (NCDOT)’s practice and experience of geotechnical aspects of design-build projects. NCDOT’s general design-build contract process and major items of a typical geotechnical scope of work are presented. The cost of geotechnical investigation work for nine design-build projects is reviewed and compared with the NCDOT’s practice for conventional contract projects. Also, foundation design and construction records of two of the nine projects are presented as a case study and discussed in comparison with the in-house design practice. This study finds that NCDOT spent 0.18 - 1.15 % of total contract price for eight of the nine design-build projects, which is much lower than the typical 3 - 5 % for conventional contract projects. However, the pre-let subsurface investigation appears to have provided the short-listed teams with a reasonable amount of subsurface information to prepare their contract proposals. The amount of post-let subsurface investigation performed by the selected design-build contractors varied significantly from project to project. The design-build contracting method appears to be effective to speed up project delivery and reduce overall project cost; however, risk, potential reduction in quality and subsequent long-term maintenance costs associated with innovative design and construction techniques need to be evaluated carefully to assure that the benefits of design-build contracting are realized.
     Kyung Jun Kim, North Carolina Department of Transportation, kkim@ncdot.gov
     Christopher A. Kreider, North Carolina Department of Transportation
     Michael D. Valiquette, North Carolina Department of Transportation

09-3238 - High-Capacity Piles at the Stony Creek Bridge Project
Session 203
High Capacity Piles (HCP) offer a highly attractive foundation option to geotechnical designers, but they continue to present challenges to regular acceptance and wider implementation. Through a case study of the Stony Creek Bridge Project, the California Department of Transportation presents its experience with the advantages and limitations of High Capacity Piles. The motivating reasons, design considerations, construction observations and testing results at the Stony Creek Bridge are detailed to allow insight into this developing foundation choice. The 8-foot (2.44m) diameter 170-foot (51.8m) long steel piles at the Stony Creek Bridge are reputed to be the largest piles ever driven on land.
Brian A. Liebich, California Department of Transportation, brian.liebich@dot.ca.gov

09-3303 - Automation of Pavement Sublayer Moisture Content Determination Using LTPP Time Domain Reflectometry Data and Micromechanics
Session 453
Time Domain Reflectometry (TDR) is one of the reliable methods to measure in-situ moisture content of unbound base and subgrade materials. However, the waveform data obtained from TDR device does not provide in-situ moisture content directly. Rather, the data must be analyzed to determine volumetric moisture content which is final product of TDR related technology; that is, a TDR trace is analyzed to determine the value of the associated dielectric constant which is dependant upon soil surrounding the TDR probe affecting the moisture content determination. However, since existing methods to determine the dielectric constant and moisture content are immersed in systematic errors, a new approach was developed using the transmission line equation and a 3-phase micromechanics approach to improve the accuracy of the interpretation of TDR data for calculating the dielectric constant and the moisture content. Since the system identification (SID) method used to calculate parameters in the new approach is an iterative solution scheme, a computational program was required to provide a rapid, accurate, and repeatable calculation of parameters. To address this need, a program was developed to facilitate the calculation of dielectric constant, dry density, and moisture content based on the micromechanics approach. Details regarding the feature, algorithm, and result of the program are provided in this paper.
     Sang Ick  Lee, Texas Transportation Institute, s-lee@ttimail.tamu.edu
     Dan G. Zollinger, Texas A&M University
     Robert Leonard Lytton, Texas A&M University
     Newton C. Jackson, Nichols Consulting Engineers Chartered

09-3735 - Effects of Environmental Factors on Construction of Soil-Cement Pavement Layers
Session 649
The specific objectives of this research were to quantify the effects of certain environmental factors on the relative strength loss of soil-cement subjected to compaction delay and to develop a numerical tool that can be easily used by engineers and contractors for determining a maximum compaction delay time for a given project. These objectives were addressed through extensive laboratory work and statistical analyses. The laboratory work involved testing an aggregate base material and a subgrade soil, each treated with two levels of cement. Environmental factors included in the experimentation were wind speed, temperature, and relative humidity, and three levels of each were evaluated in combination with three compaction delay times. The primary response variables in this research were relative compaction and relative strength. The findings indicate that relative strength is sensitive to variability among the selected independent variables within the ranges investigated in this research, while relative compaction is not. Inferring relative strength from relative density is therefore not a reliable approach on soil-cement projects. Consistent with theory, higher wind speed, higher air temperature, lower relative humidity, and higher compaction delay time generally result in lower relative strength. With the nomographs developed in this research, the maximum delay time permitted for compaction of either a base or subgrade material similar to those tested in this research can be calculated. Knowing in advance how much time is available for working the soil-cement will help contractors schedule their activities more appropriately and ultimately produce higher quality roads.
     W. Spencer Guthrie, Brigham Young University, guthrie@byu.edu
     John E. Michener, Kimley-Horn and Associates, Inc.
     Bryan T. Wilson, Brigham Young University
     Dennis L. Eggett, Brigham Young University

Structures

09-0445 - Dynamic Loading of Curved Steel Multi-Box-Girder Bridges
Session 762
This paper presents a method for estimating dynamic loading of steel multi-box girder bridges due to moving vehicles, based on an extensive parameter analysis of 216 multi-box-girder bridges. The curved multi-box-girder bridge is modeled as a curved grillage system. The analytical vehicle, simulated as a nonlinear vehicle model with 11 degrees of freedom, is the HL-93 truck as described in the American Association of State Highway and Transportation Officials (AASHTO) specifications. Truck parameters include the body, suspensions, and tires. The bridge deck surface is assumed to be classed “good” and is simulated using a stochastic process (power spectral density function). The bridge-vehicle interaction model is validated by field test results from two curved steel box bridges. The analytical results show that the torsion impact factors for curved box girder bridges can be relatively high, while moment, shear and deflection impact factors are normally less than those of corresponding straight box girder bridges due to restricted vehicle speed on curved bridges. The proposed simplified impact equations are appropriate for the design of curved steel box girder bridges.
Dongzhou Huang PE, Post, Buckley, Schuh & Jernigan, dhuang@pbsj.com

09-1303 - Structural Health Monitoring of Three Bridges in Connecticut
Session 580
This report discusses the implementation of long-term structural health monitoring systems on three bridges in the State of Connecticut. The project began with the development of a generic set of guidelines for using readily available monitoring equipment to serve as a basis for designing long-term systems. These were then used to design individual monitoring systems that were tailored to each bridge, using sensors for strain, temperature, tilt and vibration. Monitoring has been conducted on a continuous basis, with excitation provided by normal traffic loading. The goal has been to use long-term monitoring to learn how bridges behave over multi-year periods and to use data obtained from the monitoring systems to establish the basis for long-term structural health monitoring.
John T. DeWolf, University of Connecticut, dewolf@engr.uconn.edu

09-1313 - History of Connecticut’s Short-Term Strain Program for Evaluation of Steel Bridges
Session 762
Non-destructive strain monitoring has been used for two decades on Connecticut’s bridges to supplement visual field inspections. These studies have addressed a wide range of problems, including fatigue cracking in diaphragm connections, cracked secondary connections, main girder cracking, load ratings, over-load conditions, and concerns with movable bridges involving drive mechanisms and counter-weight supports. Monitoring has often shown that repairs are not necessary, and when necessary, the data collected in the monitoring has been used to provide information on how best to design the repair. The monetary benefits from monitoring during the past two decades has saved the State of Connecticut millions of dollars, well below the cost of implementing the monitoring program.
John T. DeWolf, University of Connecticut, dewolf@engr.uconn.edu
Michael P. Culmo P.E., CME Associates, Inc.

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