Relationship between Binder and Mixture Damage Resistance at Intermediate and Low Temperatures

The importance of binder performance in mixture response to accelerated fatigue loading and thermal cracking was investigated. Binder fatigue performance was measured by means of the linear amplitude sweep test, and fatigue properties of the mixtures were investigated by performing a strain sweep test. The low-temperature properties of the binders were investigated by measuring the glass transition temperature and fracture properties with the single-edge notched beam (SENB) test. The mixtures' fracture properties were investigated by using the FENIX test. The experimental matrix for this study included unmodified and modified binders and limestone aggregates. A good correlation between binder and mixture fracture energy was observed at low temperatures. This good correlation indicates the importance of the fracture response of the binder to the overall low-temperature cracking performance of the mixture. Experimental results suggest that a significant part of the variation of the fracture energy of the mixture can be explained by the binder fracture properties. Good correlations were also obtained for the displacement at maximum load in the SENB and FENIX tests. Similar accelerated fatigue responses for binders and mixtures were observed when the stresses and strains were normalized. Significant reduction in stress occurred at about the same normalized strain in the binder and mixture. The mixture had remaining strength after reaching peak stress, probably as a result of the aggregate structure.