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Chip seals are often applied to asphalt pavements to add skid resistance to the surface and increase the durability of the road. Many transportation agencies have found that adding crumb rubber to the mixture can increase performance, but the high temperatures required for application can pose a potential safety hazard for maintenance crews.

To achieve the desired performance results at a lower application temperature, the Louisiana Department of Transportation and Development conducted a research project to evaluate a modified asphalt emulsion using recycled tire rubber. With a cooler application temperature, the tire rubber emulsion may be a worker-friendly alternative to crumb rubber.

Read the report: Evaluation of Asphalt Rubber and Reclaimed Tire Rubber in Chip Seal Applications, April 2022.

Image source: Louisiana DOT

The Transportation Research Board’s Standing Technical Committee on Roadside Maintenance will host a free webinar, “Roadside Fire Risk and Prevention Strategies” on Thursday, July 7 from 12:30 – 2 p.m. Eastern.

Presenters will share roadway designs and vegetation management strategies that can significantly reduce the risk of fires from vehicles and discarded cigarettes without compromising stormwater quality or increasing erosion.

Learn more and register.

Image source: Caltrans

Inspectors charged with assessing the condition and maintenance needs of steel cables embedded in concrete bridges may employ the magnetic flux leakage (MFL) test, using strong magnets to detect corrosion in areas they can’t see directly. However, other metal components of the bridge can interfere with the test and affect the readings.

To improve the test and increase the accuracy of the MFL test results, Florida DOT partnered with university researchers to identify advancements in this testing method.

With the ability to detect issues early and more accurately, the agency will be better able to prioritize maintenance activities that will extend the performance of bridges across the state.

Read the research summary: Magnetic Flux Leakage (MFL) Method for Damage Detection in Internal Post-Tensioning Tendons, May 2022.

Image source: Florida DOT

For decades, South Carolina DOT has relied on pavement performance models to anticipate future maintenance needs and budget accordingly.

Given changes in pavement materials and practices, as well as improved data collection technologies, the agency sought to determine whether the models still provide accurate predictions.

Finding that modern pavements are slower to degrade than previously thought, the agency will be better positioned to conserve its limited resources.

Read the report: Pavement Performance Curves: Modeling Pavement Deterioration for SCDOT, February 2022.

Image source: South Carolina DOT

 

For crews performing road maintenance and repair activities, fast-moving traffic can pose a serious hazard.

Temporary rumble strips offer a flexible solution for slowing vehicles near work zones. To understand how well the devices improve driver behavior, the Missouri DOT evaluated different configurations of short- and long-term varieties and surveyed other state DOTs about their experiences.

The study found temporary rumble strips to be generally effective and revealed a variety of best practices to maximize their influence and durability.

Read the report: Effectiveness of Temporary Rumble Strips in Work Zones, February 2022.

Image source: Georgia DOT

Several No Boundaries member states received recognition in the May/June 2022 issue of Innovator, the Federal Highway Administration’s bimonthly newsletter.

Connecticut DOT was noted for its work with digital as-builts. By cataloging all of its infrastructure assets into a geographic information systems database, the agency is providing real-time data to help maintenance crews make better-informed decisions when it comes time to repair or replacement.

Texas DOT’s success with crack attenuating mixtures was also highlighted. This type of pavement overlay has been shown to slow the rate of reflective cracking by as much as 50 percent.

Finally, Wisconsin and Virginia were applauded for their use of State Transportation Innovation Council (STIC) funds. In Virginia, these funds have been used to install fencing along highways to reduce collisions between vehicles and wildlife, while the Wisconsin DOT was able to develop and implement its Standard Bridge Design Tool using STIC funding.

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Image source: FHWA