Effect of the filler particle size on the low and high temperature performance in asphalt mastic and concrete

Restrained cooling, time-to-failure and triaxial tests were conducted on mastics and dense and gap-graded asphalt mixtures prepared with two different fillers (coarse and fine fillers). Little variation in thermal stress response or time to failure was observed between samples with different gradations in mastic and mixture restrained cooling tests. Failure stresses and temperatures were identical for different mastics and mixtures, despite the large differences in fines gradations, lending indirect support to the view that the crack pinning theory is relevant to the low-temperature failure of asphalt mastics and mixtures. Mixtures produced with coarse filler and less natural sand had ∼ 50% less permanent deformation than those with fine filler and more natural sand due to the presence of gaps and the lower amount of natural sand in the mixture made with coarse filler. Significant performance differences existed between different mixtures with identical gradations above the 75-μm cut-off limit.