Rheological properties of Colemanite compound modified bitumen and its effects on bituminous mixtures

The utilization of boron in bituminous mixtures has attracted attention as an innovative approach in recent years. A novel additive material Organic-based Colemanite Compound (ColCom) was synthesized chemically by Colemanite, a boron mineral, and monoethylene glycol under laboratory conditions in the study. The base bitumen was modified with ColCom up to 8% by wt at 150℃ for 20 min, providing advantages in terms of modification parameters. The effects of ColCom on the performance of bitumen and bituminous mixtures were investigated through rheological and mechanical tests including Rotational Viscosity, Penetration, Softening Point, Elastic Recovery, Force-Ductility, Dynamic Shear Rheometer, Bending Beam Rheometer, Nicholson Stripping, Marshall, Indirect Tension, Modified Lottman and Hamburg Wheel Tracking tests. ColCom contributed to the fluidity of bitumen at plant temperatures by reducing its viscosity up to 48% and to the rheology of bitumen at high service temperatures by making it more stiff. The rutting and low temperature cracking resistances of the base bitumen were increased up to 64% and 45% respectively by ColCom, improving performance grade (PG) from PG 64–16 to PG 70–22. The positive effect of ColCom on fatigue resistance was found to be partial. Besides, the stripping resistance, stability, moisture resistance and rutting resistance of the bituminous mixtures were enhanced through ColCom modifications. • We synthesized a novel additive material chemically: ColCom. • Base bitumen was modified by ColCom. • Effects of ColCom on bitumen and bituminous mixtures were experimentally examined. • Bitumen rheology and bituminous mixture performance were improved by ColCom. • ColCom offers roadway pavements the potential to better withstand loadings.