Enhancing the performance of cold bitumen emulsion mixtures with coir and glass fibres: Experimental and numerical analysis

Cold bitumen emulsion mixtures (CBEMs) offer significant benefits over hot mix asphalt (HMA), including sustainable energy consumption, eco-friendliness, and cost-effectiveness. However, their adoption is limited due to prolonged curing times and low early-life strength. This study examines the reinforcing process of CBEMs with both coir fibres as eco-friendly waste additives and glass fibres as synthetic additive to enhance crack resistance and prolong pavement life. The developed CBEMs are evaluated in terms of tensile strength, creep behavior, fracture toughness, and rutting resistance, using an optimal fibre length of 15 mm and a content of 0.4% by the aggregate weight. Employing both coir and glass fibre reinforcement within CBEMs led to increase the tensile strength by 47% and 87%, respectively. Creep strain was reduced by 33.3% and 56.7% at 60° C after 4000 seconds, while at 40° C, the reductions reached 10% and 66.7%. Fracture toughness increased by 52% and 85%, and rutting depth decreased by 43% and 56%, respectively. The best results were achieved by the glass fibre-reinforced CBEM, which exhibited the highest structural performance, durability, and moisture resistance. The implemented finite element modelling (FEM) using ABAQUS software strongly aligns with experimental results in terms of performance behavior. The adopted statistical analysis confirmed considerable alignment between experimental and numerical results regarding fracture toughness and crack length, thereby validating the reliability and accuracy of the FEM approach.