Preventing pavement failure caused by HMA temperature differentials: Washington State.

In recent years, large numbers of hot-mix asphalt (HMA) paving projects in the United States and around the world have experienced premature failure through fatigue cracking, raveling, or both, which can be costly to fix on high-volume interstate routes.

Observations in the State of Washington

and elsewhere suggest that construction-related temperature differentials that produce low-density areas are susceptible to isolated damage in an otherwise serviceable pavement. Research and records in the Washington State Department of Transportation (WSDOT) pavement management system show that temperature differentials, depending on the severity, can reduce expected pavement life by 20 to 80 percent. As a result, WSDOT began research that culminated in the development of a three-step specification to counter the detrimental effect of temperature differentials. The cost savings are difficult to estimate; however, if reducing temperature differentials could prevent a potential 20 percent loss of pavement life on half of the State's projects, the savings would amount to approximately $9 million per year.

For more information, see Preventing Pavement Failure Caused by Hot-Mix Asphalt Temperature Differentials: Washington State's Systematic Approach online at http://onlinepubs.trb.org/onlinepubs/trnews/trnews246rpo.pdf.

Transportation Research Board