Enhancing Asphalt Mix Solubility with Sodium Bicarbonate Leavening in Vulcanized Rubber: A Regulatory-Compliant Approach

Abstract

Abstract In this research, sodium bicarbonate (NaHCO3) was used as a leavening agent to create air voids in the rubber-vulcanized matrix. The air cavities formed will increase the solubility of rubber vulcanizate in the hot asphalt mixture. 4 and 5 per hundred rubber (phr) NaHCO3 were added to each rubber compound using an open mill. The rubber compound was then vulcanized at 130°C for 15 minutes. Rubber vulcanizate is produced from 4 and 5 phr NaHCO3, each added at 8% to a hot asphalt solution. As a comparison material to determine the performance of NaHCO3, a rubber compound formula was prepared without using NaHCO3. It was found that the AK-01 sample containing NaHCO3 at 4 phr had several characteristics that met the requirements of Indonesian rubber asphalt regulations, including a softening point of 59.7°C, kinematic viscosity at 135°C of 828 cSt, elasticity after recovery of 30%, storage stability, a softening point difference of 2.2°C, and elasticity after the return of the thin film oven test (TFOT) residue test of 40%.