About $1.5 trillion will be spent globally on airport infrastructure by 2030, a ccording to the International Air Transport Association.  Most of that enormous amount of money will be spent on projects that must be constructed without disrupting airport operations. Given the focus on schedule and on the cost of failing to complete the construction during the periods of planned outages, the...

Concrete is a porous material that allows materials to move through it. The number of pores connected in the concrete, also known as the permeability, influences the ability of fluids to penetration the concrete. And this permeability parameter is an important transport mechanism for freeze-thaw damage, corrosion, alkali silica reaction, and sulfate attack. The TRB Innovations Deserving Explora...

Global business and tourism depend heavily on the efficient operation of airports and movement of passengers, baggage, and cargo across many areas. With increasing demand and connectivity requirements for airports comes the need for more sophisticated simulation and modeling tools to validate design assumptions. Furthermore, airport design and planning decisions have significant impacts on poli...

The performance of flexible and rigid pavements is known to be closely related to properties of the base, subbase, and/or subgrade. However, some recent research studies indicate that the performance predicted by this methodology shows a low sensitivity to the properties of underlying layers and does not always reflect the extent of the anticipated effect, so the procedures contained in the Ame...

TRB’s Technical Activities Division has released Transportation Research Circular E-C249: Key Elements of Construction Quality Assurance for Implementation, presenting a synopsis of " Quality Assurance: There’s Value in the Basics," held at the 2018 Annual Meeting of the Transportation Research Board. In this session, four speakers with a range of perspectives—the Federal Highway Administration...

The uses and levels of maturity of five advanced technology areas visualization and modeling, interconnected technologies, safety technologies, instrumentation and sensors, and unmanned aircraft systems in transportation highway construction projects are documented in TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 534: Emerging Technologies for Construction Delivery. The ...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 537: Impact of Asphalt Thickness on Pavement Quality documents transportation agency policy for lift thickness and minimum compaction requirements on resultant asphalt pavement quality. To achieve expected pavement performance, it is important that asphalt concrete (AC) have adequate density. A critical factor in achieving th...

TRB Special Report 330: Performance of Bridges That Received Funding Under the Innovative Bridge Research and Construction Program, examines the results of a federal program to promote innovation in highway bridge construction. The report provides recommendations to Congress on how the installed and life-cycle costs of bridges could be reduced through the use of innovative materials and technol...

TRB’s National Cooperative Highway Research Program (NCHRP) Research Report 908: Acceptance Criteria of Complete Joint Penetration Steel Bridge Welds Evaluated Using Enhanced Ultrasonic Methods presents guidelines for evaluating complete joint penetration (CJP) welds in steel bridges and proposes modifications to the American Association of State Highway and Transportation Officials (AASHTO)/Am...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 536: Bridge Demolition Practices documents practices used by bridge owners to manage and administer bridge demolition in construction projects. Each year hundreds of bridges are rebuilt or are entirely replaced as part of highway construction projects. Bridge reconstruction or replacement work often entails demolition of part...

TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 260: Proposed Refinements to Design Procedures for Geosynthetic Reinforced Soil (GRS) Structures in AASHTO LRFD Bridge Design Specifications explores the effect of adopting a closely‐spaced reinforcement layout in geosynthetic‐reinforced soil structures. While research since the early 1980s has identified the benefici...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 894: Performance of Longitudinal Barriers on Curved, Superelevated Roadway Sections  presents guidance on designing, selecting, and installing longitudinal traffic barriers for curved, superelevated roadways for possible incorporation in the American Association of State Highway and Transportation Officials (AASHTO...

TRB has released Critical Issues in Transportation 2019 . In this report, which is updated periodically by the TRB Executive Committee, a series of challenging questions are posed to explore issues and opportunities that may arise 10 to 20 years into the future. These questions, 63 in all, have been organized into 12 topic areas and provide a way to frame future areas of research, policy analys...

TRB Special Report 329: Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future explores pending and future federal investment and policy decisions concerning the federal Interstate Highway System. Congress asked the committee to make recommendations on the “features, standards, capacity needs, application of technologies, and intergovernmental roles to up...

The latest edition of Research Pays Off explores how to evaluate the impact of transportation projects on residential subdivisions. The TR News is TRB's bimonthly magazine featuring timely articles on innovative and state-of-the-art research and practice in all modes of transportation. It also includes brief news items of interest to the transportation community, research pays off articles that...

The full edition of the July–August 2018 TR News is now available. This edition examines 20 years of research and TRB activities on alternative contracting methods (ACM) and success stories from implementing research innovations. Explored are pioneering tools and contracting techniques used by state departments of transportation such as Georgia and Colorado, along with tested project delivery m...

TRB's Airport Cooperative Research Program (ACRP) latest Impacts on Practice explores the impact ACRP Synthesis 39 : Airport Wildlife Population Management has had on integrated wildlife management plans at airports. A wildlife biologist at Orlando International Airport utilized this report to develop a holistic approach to mitigating bird strikes with a specific species of heron that thrives i...

Transportation Research E-Circular 237: Innovations in Asphalt Mixture Design Procedures explores the fundamentals of asphalt mix design for improved durability and performance. Based off of presentations made at TRB's 95th Annual Meeting, the document examines presentations that cover ways to incorporate more binder into the mix with trials that modify the air void and void in mineral aggregat...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 890: Using Recycled Asphalt Shingles with Warm Mix Asphalt Technologies documents the development of a design and evaluation procedure that provides acceptable performance of asphalt mixtures incorporating warm mix asphalt (WMA) technologies and recycled asphalt shingles (RAS)—with and without recycled asphalt pave...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 257: A Mechanistic–Empirical Model for Top–Down Cracking of Asphalt Pavements Layers develops a calibrated mechanistic-empirical (ME) model for predicting the load-related top-down cracking in the asphalt layer of flexible pavements. Recent studies have determined that some load-related fatigue cracks in asphalt pavem...

TRB's National Cooperative Highway Research Program (NCHRP) Innovations Deserving Exploratory Analysis (IDEA) Final Report 186: Development of an Electrical Probe for Rapid Assessment of Ground Improvement explores new technologies that can be used in soil improvement. Soil improvement has numerous applications in transportation construction, including embankment stabilization, underpinning bri...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 878: Validation of the Louisiana Interlayer Shear Strength Test for Tack Coat evaluates and validates a test method to determine the interlayer shear strength of asphalt pavement layers. The report includes three appendices documenting the field project checklist, photos of existing pavement distress in two states, and ...

TRB's National Cooperative Highway Research Program (NCHRP)  Web-Only Document 247: Managing Geotechnical Risks in Design–Build Projects documents the research effort to produce NCHRP Research Report 884 : Guidelines for Managing Geotechnical Risks in Design–Build Projects. NCHRP Research Report 884 provides guidelines for the implementation of geotechnical risk management measures for des...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 884: Guidelines for Managing Geotechnical Risks in Design–Build Projects provides guidelines for the implementation of geotechnical risk management measures for design –build project delivery . The guidelines provide five strategies for aligning a transportation agency and its design–builder’s perception of geotechnical...

TRB's E-Circular 235: Glossary of Transportation Construction Quality Assurance Terms: Seventh Edition contains common terms and accepted practice in transportation construction quality assurance terminology. Transportation construction quality assurance (QA), like many other specialized subject areas, has its own unique language containing numerous technical terms or expressions having very sp...

TRB's E-Circular 234: Relationships of Laboratory Mixture Aging to Asphalt Mixture Performance summarizes the results from TRB Session 462: Relationship of Laboratory Mix Aging to Asphalt Mixture Performance, which was held during the 2016 TRB Annual Meeting. This circular includes four papers on addressing laboratory mix aging and explore handling asphalt mixtures at a production facility, var...

The latest edition of Research Pays Off explores the Georgia Department of Transportation (DOT)'s use of alternative delivery methods to compress and accelerate the delivery of projects from engineering through construction through public–private partnerships (PPPs) and design–build (DB) methods.This article discusses the legislation that allowed Georgia DOT to build partnerships with private f...

A featured article in the July-August 2018 issue of the TR News investigates how risk is addressed in both the traditional project delivery method and in alternative project delivery methods used by departments of transportation across the country.  The TR News is TRB's bimonthly magazine featuring timely articles on innovative and state-of-the-art research and practice in all modes of tra...

A featured article in the July-August 2018 issue of the TR News examines the latest application and implementation of alternative contracting methods for faster project delivery of transportation infrastructure. The TR News is TRB's bimonthly magazine featuring timely articles on innovative and state-of-the-art research and practice in all modes of transportation. It also includes brief news it...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 518: Staffing for Alternative Contracting Methods documents current practices in state departments of transportation (DOTs) staffing and organizational structure for alternative contracting methods (ACMs). ACMs include design–build, construction manager/general contractor, public–private partnerships, and other innovative con...