Behaviour of high-modulus asphalt concrete from the perspective of deformation characteristics - Stiffness

Abstract

High-modulus asphalt concrete is a specific type of asphalt mixture which is used for several decades in pavement engineering. It was originally invented as a solution which should help to minimize the effects of permanent deformation caused mainly by heavy traffic and mainly during the periods with elevated temperatures. These mixtures are used either in binder or base courses, whereas for base courses, it is important to combine reasonably the high stiffness with good fatigue life to avoid premature pavement failures not caused by rutting but by fatigue cracking. In this respect, various types of HMAC used and designed in the Czech Republic were tested first and foremost to determine stiffness. The stiffness modules were tested according to EN 12607-26, test method IT-CY, at selected temperatures representing cold, moderate and high service temperatures. The susceptibility to temperature change can be shown by thermal susceptibility for each mixture. In the parallel test, specimens were laboratory age to identify the changes in stiffness caused by thermo-oxidative ageing. This allows calculating a simple measure of the ageing index. Not presented in this paper but performed as a very last test was resistance to crack propagation.