Development of a Laboratory Screening Test for Asphalt Pavement Crack Sealants

Premature failure of crack sealants and fillers in the field calls into question the effectiveness of these materials as a treatment for cracked asphalt concrete (AC) pavements. Although standard sealant test methods ensure the consistency of the product, they fail to account for the ability of the sealant material to bond to AC, especially at cold temperatures after the material has aged. In an attempt to evaluate this behavior, a study was undertaken at Michigan Technological University, through sponsorship by the Michigan Department of Transportation. This study’s objective was to develop a laboratory testing protocol to evaluate crack sealants and fillers in an attempt to obtain better predictions of field performance. The developed protocol tests sealed AC blocks at a low temperature before and after accelerated laboratory aging to assess stiffening and failure characteristics in tension of the sealant and filler materials. To date, four laboratory phases have been completed to verify the repeatability of the testing, and preliminary correlation has been made with limited field data. The results indicate that the developed protocol is able to measure relative sealant performance in various configurations, but it is not possible to establish definitive relationships between laboratory testing and field performance at this time. Additional testing of materials, with an emphasis on field correlation, will be necessary to calibrate the test procedure.