The rutting performance of cold bitumen emulsion mix using ground granulated blast furnace slag and lime as fillers

Abstract

Rutting is a worldwide recognized distress in bituminous pavement caused by repetitive passage of traffic loads at high temperature. High air voids and poor early strength of cold bitumen emulsion mix (CBEM) can cause rutting deformation even at lower temperatures, making it undesirable to practitioners. The CBEM can be effectively modified by using hydraulic materials as filler. The present study examines the effect of ground granulated blast furnace slag (GGBFS) and lime as fillers on rutting characteristics of CBEM at varying temperatures (i.e., 40, 50, 60oC). The conventional stone dust (SD) filler was partially replaced by GGBFS. For further modification, lime was added in CBEM containing GGBFS. Initially mix were selected for rutting test based on the results obtained by Marshall stability, indirect tensile strength, retained Marshall stability, and tensile strength ratio tests. Based on these results, 80% of GGBFS was optimized for CBEM production. Incorporating 20% lime with 80% GGBFS in CBEM further improved the properties mentioned above. Both mixes were selected for the rutting test, along with CBEM containing 100% SD and CBEM containing 20% lime, which were also selected for comparison purposes. Wheel tracking device was used for rutting test on CBEM at varying temperatures. Based on results, it was found that increasing testing temperature increases the rutting deformation. However, the CBEM containing GGBFS and lime by 80% and 20% of total weight of filler in the mix, respectively, gave better rutting resistance at each testing temperature and provide less temperature sensitivity. So, this paper introduces the blended GGBFS and lime as a new composition in CBEM that provides improved laboratory strength, moisture susceptibility resistance, and rutting resistance.