Laboratory Study on Modified Bituminous Binders and its Mixes

This book studies the procedure for modifying 80/100 penetration grade bitumen using various percentages of Crumb Rubber (CR) and High-density Polyethylene (HDPE) modifiers. Physical properties of modified bitumen with different percentage (2% to 8%) of CR and HDPE were evaluated. It is found that the penetration value, softening point and elastic recovery of bitumen can be improved significantly by adding CR and HDPE. Marshall Stability method is adopted for mix design and the mechanical properties of the modified bituminous mixes are determined. The stability is improved by 45% when HDPE+CR were mixing together. Marshall retained stability and indirect tensile strength tests were conducted to determine the ability of the modified mixes to withstand adverse soaking conditions. There was significant improvement in Retained Stability (%) and Indirect Tensile strength ratio due to lesser voids present in bituminous mixes containing CR and HDPE thus resulting in reduction in water permeability.