TRB's National Cooperative Highway Research Program (NCHRP) Research Report 877: Performance-Based Mix Design for Porous Friction Courses presents a proposed mix design method for porous asphalt friction course (PFCs). PFCs have been used in the United States for many years. Their open aggregate gradations and resultant high air void contents provide PFCs with the ability to quickly remove water from the surface of a roadway, thus reducing the potential for vehicles to hydroplane and improving skid resis...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 515: Practices for Preventing Roadway Departures identifies and summarizes practices being used by state departments of transportation (DOTs) to prevent roadway departure crashes and to identify the data-driven advantages and disadvantages of these practices. More than half of all traffic fatalities result from roadway departure crashes. This type of crash occurs after a vehicle crosses an edge line or centerline or otherwise leaves th...

The National Cooperative Highway Research Program (NCHRP) Innovations Deserving Exploratory Analysis (IDEA) Final Report 193: DART Field Validation and Prototype Refinement documents a study to validate a field-ready prototype of the Duomorph Asphalt Rheology Tester (DART) as a low-cost and easy-to-use asphalt binder testing device. The DART system has the potential to provide a cost-effective way to monitor the uniformity or specification compliance of asphalt binder samples at various points along its ...

TRB's Transportation Research Record: Journal of the Transportation Research Board has released more than 200 papers from the 2018 TRB Annual Meeting. Enhancements to the journal include:  Articles published much closer to final acceptance A new user interface for the journal Article-level metrics  Full-text HTML to enhance discovery of the research Interactive proof markup for authors LaTeX support for complex math articles (LaTeX is a typesetting system that includes features designed for the...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 516: Tack Coat Specifications, Materials, and Construction Practices provides state agencies across the United States with guidance as they reevaluate their tack coat specifications, the materials they use, and the practices by which the tack coats are placed. Pavement thickness design assumes that pavement works together as one layer, rather than a stack of individual layers working independently. Tack coats function as bonding agents...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 871: Long-Term Aging of Asphalt Mixtures for Performance Testing and Prediction presents a proposed standard method for long-term laboratory aging of asphalt mixtures for performance testing. The method is intended for consideration as a replacement for the method in AASHTO R 30, “Mixture Conditioning of Hot Mix Asphalt (HMA),” which was the most commonly used method for aging asphalt materials for performance testing for input t...

To keep pace with accelerating rate of research distribution, the Transportation Research Record: Journal of the Transportation Research Board is now publishing articles as soon as they are finalized. The latest papers to be published are as follows: Use of a Laser Diffractometer to Obtain the Particle Size Distribution of Fine-Grained Soils Interstate Speed Profiles Conditioning and Testing Protocol Combinations to Detect Asphalt Mixture Damage Safety Evaluation of the SafetyEdge Treatment for Pavement ...

The full edition of the July–August 2017  TR News  magazine is now available.  Moving research into practice is the theme of feature articles in this edition. Authors describe today’s successes, present a systematic approach that has proved effective at a state department of transportation, describe federal programs encouraging innovations at the state level, discuss initiatives by research programs to promote and document the implementation of results, and offer insights on technology tra...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 863: Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete  presents procedures for determining material properties of cold-recycled asphalt mixtures for input to pavement structural design programs. Highway agencies are placing increasing emphasis on sustainability, recycling, and making maximum use of existing pavement assets in rehabilitation strategies. Such emphasis has led agencies t...

TRB’s Transportation Research Record: Journal of the Transportation Research Board, No. 2632 consists of 15 papers that explore asphalt, including: Performance-Related Specifications for Asphalt Emulsions Used in Microsurfacing Treatments Chemical, Microstructural, and Rheological Characterizations of Binders to Evaluate Aging and Rejuvenation Statistical Analyses of Aggregate Mineral–Binder Adhesion: Measuring with Particle Probe Scanning Force Microscopes Evolution of the Surface Performance-Graded Spe...