Laboratory Investigation of Different Standards of Phase Separation in Crumb Rubber Modified Asphalt Binders

Abstract

The phase separation between polymer additives and virgin asphalt binders during hot storage is an important issue in the asphalt industry. Traditionally, it has been customary to evaluate the degree of phase separations in polymerized asphalts by laboratory testing, such as the cigar tube test (CTB). However, the test circumstances, temperature, and storage time vary depending on different standards used in many countries. Based on a comprehensive literature review, the range of temperatures and oven storage times were selected to be 140–180°C and 2–7 days, respectively. The phase separation of 11 storage stability conditions selected from 12 different places using crumb rubber modified asphalts (CRMAs) were compared and evaluated in this study. The CRMAs produced in the laboratory were made with PG 64-22 virgin binder and ambient crumb rubber with various concentrations (10, 15, and 20% by weight of virgin binder). The CTB was used as the storage stability test method, and percent separation was obtained from the