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...

Transit state of good repair (SGR) is a critical area within the U.S. transit industry. All transit agencies, large or small, regardless of region of the country or modes operated, face challenges in maintaining their physical assets in good repair, and many are in a situation where the funds available for rehabilitating and replacing existing capital assets are insufficient for achieving SGR. ...

Identifying the location, size, and extent of weld defects or flaws can be critical for ensuring bridge safety. Current bridge-inspection practice relies primarily on visual inspection for detecting cracks but is not capable of detecting subsurface weld defects that may develop into cracks under service loading. Other technologies such as conventional ultrasonic testing (UT) and radiographic te...

Information exchanged during the 97th Annual Meeting of the Transportation Research Board in a session titled "Relationship Between Laboratory Cracking Tests and Field Performance of Asphalt Mixtures" is captured in Transportation Research Circular E-C251: Relationship Between Laboratory Cracking Tests and Field Performance of Asphalt Mixtures . The document explores a significant amount of wor...

Traditionally, pavement management decision-making has relied on surface cracking as an indicator of structural condition. However, with early-intervention preservation activities to extend the life of pavements, surface cracks no longer are a reliable indicator of structural condition. In the past 15 years, traffic speed deflection devices (TSDDs) have been developed to measure pavement struct...

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...

Airports continually balance demands to improve infrastructure within the realities of available budgets. Green revolving funds (GRFs) offer an alternative approach for investing in projects that generate operational savings. These funds work by tracking verified cost reductions from implemented actions, and then transferring those savings to a reserve that provides capital for future qualified...

“Pavement condition data” are essential inputs to the process of managing airport pavements and ensuring safe operations. The technology available today to collect pavement condition data is considerably different from that available even 20 years ago, and new technologies are being developed and introduced into practice at a rapid pace. ACRP Research Report 203: Guidelines for Collecting, Appl...

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...

Although general aviation airports have historically been funded by federal, state, and local entities, the private sector is increasingly playing a larger role. This involvement has ranged on a continuum from service and management contracts to singular projects at airports that involve leasing mechanisms to long-term leases and the whole-scale private development of general aviation airports....

Public–private partnerships (P3s) can provide solutions to the project delivery challenges faced by state departments of transportation (DOTs) and local transportation agencies in delivering surface transportation infrastructure by aligning risks and rewards between public and private sectors, accelerating project delivery, improving operations and asset management, realizing construction and o...

Some concrete pavements commonly used at airports are susceptible to the destructive effects of alkali-silica reaction ( ASR).  The presence of ASR on concrete pavements can have a devastating effect on pavement performance, not only in terms of reduced functionality, but also in terms of shortened service lives.  The focus of  ACRP Synthesis 96:   Practices to Mitigate Alka...

TRB’s Technical Activities Division has released Transportation Research Circular E-C248: 12th International Conference on Low-Volume Roads, highlighting topics including road surfaces, geotechnology, cold regions and climate change, pavement management, planning and economics, unpaved roads management, geosynthetics in low-volume roads, drainage and stream crossings, climate change resiliency,...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 531 documents agency practices, challenges, and successes in conducting automated pavement condition surveys. The report also includes three case examples that provide additional information on agency practices for conducting automated pavement surveys. Pavement condition data is a critical component for pavement management s...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 533 identifies the current state of practice among state departments of transportation (DOTs) regarding selection and setup of very short duration work zone (VSDWZ). The report presents case examples of four state DOTs along with an in-depth analysis of the VSDWZ policies of these states. The case example agencies have develo...

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's Highway Innovations Deserving Exploratory Analysis (IDEA) Program Final Report 189: A Novel Vision Sensor for Remote Measurement of Bridge Displacement explores the development of a camera-based computer vision sensor system for remote measurement of multipoint bridge displacements in outdoor environments. The vision sensor tracks the movement of natural targets on the structure from a co...

TRB’s National Cooperative Highway Research Program (NCHRP) Research Report 912: Guidelines for Detection and Remediation of Soluble Salt Contamination Prior to Coating Steel Highway Structures consolidates practical guidance on the detection and remediation of soluble salt contamination prior to coating steel highway structures. Soluble salts are those that dissociate in solution into anionic ...

TRB's Rail Safety Innovations Deserving Exploratory Analysis (IDEA) Safety Project 35: Non-contact Deflection Monitoring System for Timber Railroad Bridges summarizes a project that explored the feasiblity of the methodology. Considering the abundance of timber railroad bridges in the nation that have exceeded their design life, a cost-effective and safe deflection monitoring system would be he...

TRB’s Conference Proceedings on the Web 25: Proceedings of the 12th National Conference on Transportation Asset Management is a compilation of the presentations and summary of the ensuing discussions at a July 14–15, 2018, meeting held in San Diego, California. During the meeting, attendees explored the development of integrated investment decisions within an uncertain financial planning enviro...

The National Academy of Sciences, Engineering, and Medicine has released a report that documents the status and promising future directions of materials research in the United States in the context of similar efforts worldwide. This third decadal survey in materials research reviews the progress and achievements in materials research and changes in the materials research landscape over the last...

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 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) 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) Research Report 858: Quantifying the Effects of Preservation Treatments on Pavement Performance presents a proposed framework that uses performance measures to quantify the changes in pavement performance in terms of condition, service life, and life-cycle costs. Pavement preservation provides a means for maintaining and improving the ...

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...