Effects of Basalt and Hydrated Lime Fillers on Rheological and Fracture Cracking Behavior of Polymer Modified Asphalt Mastic

Abstract

This paper investigates the influence of basalt (B) and hydrated lime (HL) fillers on the rheological and fracture performance behavior of asphalt mastics. A polymer modified asphalt (PMA) binder (PMB-4), basalt (inert filler), and hydrated lime (active filler, are considered for preparation of PMA mastic. Five different combinations of B and HL fillers are selected for the preparation of different PMA mastics with filler:binder ratio of .8∶1 (22.5% by volume). The rheological response of PMA mastic is investigated based on Superpave rutting factor, fatigue factor, and linear amplitude sweep (LAS) test results using a dynamic shear rheometer (DSR). Fracture characterization of PMA mastics is evaluated using a double-edge notched tension (DENT) test. Hydrated lime significantly improves rut resistance of PMA mastics at high temperatures. Superpave fatigue factor and LAS test results show that PMA mastic containing high dosages of HL (1–2%) has low resistance to fatigue cracking and is more susceptible to strain amplitude at intermediate temperatures. Mastic without HL predominantly shows better fracture resistance behavior with good critical tip opening displacement (CTOD) value than does PMA mastic containing high dosages of HL (1–2%). High dosages of HL (1–2%) increase high-temperature aging susceptibility by influencing the rheological performance. The PMA mastics are ranked based on various performance parameters. This study shows that the combination of B with high dosages of HL filler may not enhance the fatigue and fracture resistance of PMA mastic.