COMPARISON OF PHYSICAL AND RHEOLOGICAL PROPERTIES OF PLAIN AND CRUMB RUBBER MODIFIED BITUMEN

Abstract

Bitumen is predominantly used to construct pavements for roads, highways, and airports. Due to the viscoelasticity nature of bitumen, it plays a predominant role in the performance of the pavements where temperature and rate of load application have a great influence. In India, the specifications for bituminous binders rely on different empirical tests which have almost no significance on their performance characteristics are reported. In this paper, the physical and rheological properties of bituminous binders commonly used in India, at high and intermediate field temperatures are reported in terms of their performance characteristics. Considering several factors that affect the behavior of bituminous binders, the effects of variations in temperature, rate of loading and amount of loading are considered. The changes in the properties of commonly used grades of (60-70) bitumen both unmodified and modified with crumb rubber have been reported. The Marshall properties and indirect tensile strength ratio are compared for the specimens prepared at optimum binder content (OBC) for bituminous concrete (BC) grading-2. Crumb rubber modified bitumen shows higher Marshall Stability, reduced flow, higher ITS ratio and improved rheological properties in terms of rutting. Keywords: CRMB-crumb rubber modified bitumen, ITS-Indirect tensile strength, TFOT-Thin Film Oven test, DSR-Dynamic shear rheometer MSCR-multiple shear creep recovery.