DEVELOPMENT AND PERFORMANCE EVALUATION OF CRUMB RUBBER – BIO-OIL MODIFIED HOT MIX ASPHALT FOR SUSTAINABLE HIGHWAY PAVEMENTS

The asphalt industry has been perpetually challenged by its hazardous emissions and its contribution to the ongoing climate change and global warming crises. Likewise, the environment has been cumbered by the challenge of improper disposal of nondegradable solid wastes especially crumb rubber in form of scrap tyres resulting in serious environmental degradation. This research investigated the effect of modifying bitumen with bio-oil from cassava peels upgraded with a nondegradable polymer i.e. crumb rubber. Performance tests were carried out on the modified bitumen to evaluate its effect on its rheological properties. The percentage of bio-oil by volume used for modification of bitumen was 5%, 10%, 15% and 20%. Marshall Stability and flow tests were also carried out on the bio-asphalt produced. Experimental results of bitumen modification with cassava peel oil at 5%, 10%, 15% and 20% replacements showed an increment in flash point of 244°C, 250°C, 252°C & 259°C fire point of 259°C, 265°C, 269°C & 274°C and softening point values of 55°C, 55.5°C, 56.5°C & 57.5°C respectively of the base bitumen. Due to the high moisture content associated with biooils, properties such as ductility and viscosity were adversely affected. Upgrading with crumb rubber caused an improvement in the engineering properties of the base bitumen with penetration grade at 20% modification showed the resultant blend was 40/50 which is suitable for use on airport pavements.