Fracture mechanism in bitumen, modified bitumen and asphalt mixes

This paper investigates the effect of filler particle size on the fatigue and low temperature toughening mechanisms in bitumen mastics, polymer modified bitumen and asphalt mixtures by using glass spheres and limestone filler with sufficiently different gradations. The fatigue performance of the mastics investigated under constant torsional strain. Interfacial adhesion between polymer-modified bitumen and filler particles increases fatigue life. Crack healing examined during prolonged rests periods following fatigue damage. Considering the point that stiffness recovery is more rapid in mastics containing coarse filler; however, this does not translate into a significant recovery in fatigue life. Thermal stress restrained specimen tests on bitumen mastics indicate that particle size has not influence on the failure stress or failure temperature. Time to failure tests on asphalt mixtures also show no difference in low temperature performance between samples containing different sized filler.