Influence of high-surface-area hydrated lime on cracking performance of open-graded asphalt mixtures

Hydrated lime has been used in hot mix asphalt (HMA) to reduce moisture sensitivity and stripping since 1910 in the United States. During the past 40 years, researchers from all over the world have focused on this topic finding that hydrated lime can actually provide many other benefits to asphalt mixtures. In this paper, the use of a high surface area (HSA) hydrated lime as a filler in asphalt mixtures was investigated to assess the influence of lime microstructure on mixtures cracking behaviour. Two different open-graded friction course (OGFC) asphalt mixtures were prepared using different types of filler (calcium carbonate, calcium carbonate + hydrated lime and calcium carbonate + HSA hydrated lime) and tested using the SuperPave indirect tensile test protocol. The cracking behaviour of the mixtures was evaluated according to the HMA fracture mechanics approach developed at the University of Florida. The results show that HSA hydrated lime is able to improve the fracture performance of OGFC mixtures, even more significant than the traditional one.