Rubberised Bitumen In Road Construction

Abstract

The increasing traffic volume and heavy axle loading on flexible pavements require binders with improved resistance to deformation and cracking, while the accumulation of waste automobile tyres creates a persistent environmental burden. This study experimentally investigated rubberised bitumen prepared by the wet process using crumb rubber contents of 0%, 4%, 6%, and 8% by weight of bitumen. Conventional 60/70 penetration-grade bitumen and the modified binders were evaluated through penetration, softening point, and ductility tests, and the corresponding asphalt mixtures were assessed using Marshall stability and flow measurements. Increasing crumb rubber content reduced penetration from 67 to 55 (0.1 mm), increased softening point from 48 to 57 °C, and increased ductility from 78 to 89 cm. Marshall stability increased from 10.2 to 14.0 kN, whereas flow decreased from 3.8 to 3.2 mm. Within the tested range, the 8% crumb-rubber mixture produced the highest reported stability and the most favorable combination of binder stiffness, temperature resistance, ductility, and deformation response. The findings support the use of wet-process crumb rubber modification as a technically promising route for improving flexible pavement performance while diverting waste tyres from disposal. The reported conclusions are limited to the laboratory values and dosage range documented in the thesis.