Impact of Additives on the Cracking Resistance of Asphalt Mixtures

Abstract

This paper presents the results of long term investigations that evaluated the impacts of various additives on the resistance of asphalt mixtures to the two types of cracking distresses; fatigue and thermal. Even-though these investigations did not evaluate all additives on the same asphalt mixture and to the same cracking distress, the cracking resistance of asphalt mixtures with and without each type of additive are compared within the same asphalt mixture. Resistance to fatigue and thermal cracking were evaluated using flexural beam fatigue and uniaxial thermal stress and strain test (UTSST), respectively. Since cracking is a problem occurring in the latter part of pavement life, all asphalt mixtures were subjected to long-term oven aging prior to performance testing. The analysis of the data generated from this extensive study indicates that the cracking resistance of AC mixtures is impacted by several factors, including: aggregate absorption, type of WMA additive, asphalt binder modification process, and anti-strip additive.