Evaluation of warm mix asphalt using Graphene based nanomaterial modified Bitumen

Abstract

Warm-Mix Asphalt (WMA) has emerged as an environmentally sustainable alternative to newlineconventional Hot-Mix Asphalt (HMA) due to its reduced production temperature and newlinegreenhouse gas emissions. However, concerns regarding its long-term durability, moisture newlinesusceptibility, and mechanical stability still persist. This issue has prompted ongoing newlineresearch into innovative mix design strategies and the incorporation of additives in newlinebitumen to improve performance. This study aims to enhance the performance of WMA newlineby incorporating graphene-based nanomaterials like graphene oxide (GO) and reduced newlinegraphene oxide (RGO) into the bitumen as modifiers. WMA is produced using a twophase mixing process (TPMP) without chemical additives, utilizing bitumen emulsioncoated aggregates at different mixing temperatures (MTs) and different bitumen-toemulsion ratios. An 8% content of ground granulated blast-furnace slag (GGBFS) was newlineselected as the best filler based on HMA performance studies. The WMA mix prepared at newlinea mixing temperature of 120°C and a bitumen-to-emulsion ratio of 80:20 was identified as newlinethe best-performing mix. This formulation exhibited better performance in key mechanical newlinetests like marshall parameters, indirect tensile strength (ITS), tensile strength ratio (TSR), newlinerutting resistance, retained marshall stability, raveling loss, fracture resistance, and a 37% newlinelower raveling loss compared to conventional HMA, while meeting all standard code newlinerequirements, indicating improved durability, cohesive strength and performance. To newlineenhance WMA performance, bitumen was modified using GO and RGO at varying newlineconcentrations (0.1% to 0.5%). Fourier Transform Infrared (FTIR) spectroscopy revealed newlinedistinguished changes in the functional groups of the bitumen matrix after the newlinemodification. Shifts in characteristic absorption peaks and variations in intensity newlineconfirmed molecular-level interactions and enhanced oxidative resistance in both GO- and newlineRGO-modified bitumen. Rheological analysis using a dynamic shear rheometer (DSR) newlineand multiple