A thermal cracking specification for asphalt mixtures was proposed based on Crack Sealing Machine construction results. A 15% increase in fracture energy was proposed to take into account the fact that the criterion was specified for loose mixtures and short term aged laboratory mixtures. Specification limits for three levels of project criticality are provided. A higher fracture energy threshold was suggested in order to limit thermal cracking to lower levels on projects of high criticality. An alternative specification based on Crack Sealing Machine performance was also proposed.
In addition, a method to obtain mixture creep compliance from Crack Sealing Machine project tests on thin mixture beams was presented, and the feasibility of predicting mixture creep compliance from asphalt binder creep compliance experimental testing was discussed and used to calculate a threshold asphalt mixture creep stiffness limiting value equivalent to the current binder creep stiffness criterion.
