Here’s what WSDOT found after 6 years testing 9 hot-mix asphalt preventive maintenance techniques

Updated Aug 11, 2018

Road construction in progress

The Washington State Department of Transportation (WSDOT) just released the Preventive Maintenance Study – Final Report, which contains the results of a six-year study of hot-mix asphalt preventive maintenance techniques, the AASHTO Journal reports.

The tests were conducted at approximately 69 sites using cost data to help define which treatments are the most cost effective. The tests included crack sealing at 12 sites; chip sealing at four sites; wheel path chip seal patching at two sites; wheel path chip seal rut filling at five sites; chip seal plus crack sealing at two sites; dig outs at 22 sites; dig outs plus crack sealing at four sites; dig outs plus chip sealing at six sites; and blade patching at eight sites, as well as four “control sites” that received no pavement treatment.

According to WSDOT, the study showed that all of the treatments performed well and preserved the pavements for extended periods of time, but that the use of crack sealing, chip sealing, and dig outs together can extend pavement life for five years or more. Test data also indicated that crack sealing is the cheapest treatment, while the the most expensive was the combination of dig outs plus chip sealing.

The report ranked the cost to treat a strip of pavement 1 foot in length and one lane wide from least expensive to most expensive — crack sealing cost $1.14, wheel path chip seal rut filling cost $2.76, wheel path chip seal patching cost $4.44, full lane chip sealing cost $7.08, blade patching cost $10.00, dig outs cost $12.49, dig out plus crack sealing cost $13.63, and dig outs plus chip sealing cost $19.57.

Access the entire report here.