Friction Testing Focus — a harbinger of the future

Kentucky Transportation Cabinet (KYTC) leads the way among many states in its focus on asphalt pavement friction testing, and its efforts are advancing new specification requirements that will affect all pavement contractors in the state. It’s an all-out effort by the agency to make the state’s roads safer.

Future bids will need to consider how to increase the amount of polish-resistant aggregates. The agency further requires all pavement designs be submitted to a Dynamic Friction Test (DFT).

DFT is a newer, more intuitive testing tool. It measures skid resistance with a rubber-padded plate that spins at highway-level speeds before dropping onto the surface of the asphalt test sample. This important advancement in testing enables agencies and contractors to quickly evaluate aggregate sources ahead of paving rather than waiting five to 10 years for highway results. Best of all, the DFT can travel from the lab to the field for real-time data and correlation.

BATT Lab can perform the type of complex testing required by the state to help contractors meet the new polish-resistant specifications. As one of the few labs in the nation capable of delivering test results from aggregate to asphalt, BATT has been instrumental in helping KYTC contractors acquire an extensive understanding of friction testing and how to accurately apply the results.

The BATT Lab produces pavement slabs for the test and inflicts wear with a three-wheel polisher before submitting the sample to the DFT to further test its friction worthiness at various levels of polishing. Upon completion of the entire round of testing, BATT analyzes the results and provides a report within a responsive turnaround time.

West Virginia, Tennessee, Ohio, and Indiana have or are exploring DFT friction, but Kentucky is all in. Since the state relies on limestone (sedimentary type aggregate) as its primary aggregate, KYTC wants to pinpoint which aggregate sources work and which ones to avoid.

KYTC considers the DFT an invaluable tool for improving pavement design. All eyes are on KYTC and its new friction-testing specifications, and BATT is proud to be part of the effort to make our roads safer.

Expect friction testing (in addition to BMD) to continue to gain prominence in future roadway specification. KYTC has placed sections on the NCAT test track, and NCAT has led the way in the U.S. on friction testing and correlations with traffic and skid trailer data. Given the level of attention friction testing is receiving, it’s a good idea to begin establishing a relationship with a reliable testing resource.

On average, the BATT Lab can complete a friction test in 4 to 5 days. The entire testing process can determine the long-term friction properties of any aggregate or asphalt mix ahead of paving — and for a substantially lower cost, shorter time frame, and no risk to the traveling public — than waiting years to measure the pavement wear.

Contact BATT for more details and a quote from our lab.