Mechanical Analysis and Thermal Properties of Bitumen-Acacia Sap Composites

Abstract

Bitumen binder mechanical and thermal properties have been unsatisfactory. Different synthetic binder modifies that have been used to improve its performance have led to environmental problems such as incineration and landfill. Acacia sap a natural polymer and environmental friendly has been used successfully as a modifier. Composites of bitumen-acacia sap with different composition of sap percentage ranging from 0% to 62.5% cell sap were prepared by injection drawing process. The composites were analyzed by dynamic mechanical analysis (DMA) for mechanical properties, and thermogravimetric analysis (TGA) for thermal properties. It was found that the storage modulus and Loss modulus of bitumen binder increased with acacia sap loading. The glass transition temperatures were found to shift to higher values as acacia sap loading increased. The activation energies were determined from the thermogravimetric data of the bitumenacacia composites using the Broido model. Pure bitumen binder was found to have the highest thermal stability. In addition, modification of bitumen binder with 25% acacia sap loading gave optimum mechanical properties.