Investigation into the healing properties of bituminous mastics with bio-oil and steel slag

Abstract

This study evaluated the healing properties of bituminous mastics containing bio-oil derived from biodiesel production and steel slag. Various healing indices related to the complex shear modulus, fatigue life and load-induced damage were evaluated using time sweep tests with rest periods. The bio-oil showed a great capacity to reverse the ageing effects in bitumen, and the fatigue resistance of mastics improved with the bio-oil content. The impact of oxidative ageing and filler type on the stiffness properties and fatigue resistance varied depending on the mastic composition. The mastics were unable to fully recover their initial state under the resting conditions applied, and healing capacity decreased with each successive loading period. The most significant effect of the rest period was observed in the healing index related to the complex shear modulus, suggesting that this healing index accounts for a large proportion of the non-damaging effects associated with cyclic loading. The healing capacity was generally higher for the mastics containing bio-oil, although the degree of improvement varied depending on the mastic composition and the specific healing index considered. The influence of filler type on healing capacity was relatively minor, however, steel slag powder was shown to be a viable alternative to limestone filler.