Strength and ductility behaviour of rubberised cemented clayey soil

This paper reports the strength and ductility behaviour of rubber-granulate-reinforced cemented clayey soil and rubber-fibre-reinforced cemented clayey soil. The load–deformation behaviour of specimens was analysed in terms of absolute toughness and toughness index (TI) for further screening of the curves. A 5·08 and 3·46% improvement in the unconfined compressive strength and 16·74 and 8·60% improvement in the split tensile strength of the clayey soil was observed with the addition of rubber granulates and fibres up to 2·5 and 5%, respectively. However, increasing the content of granulates and fibres led to reductions in strength. The rate of strength reduction in granulate-reinforced soil was found to be higher than in that containing fibre. The absolute toughness and TI of soil mixed with 5 and 7·5% of granulates and fibres were found to be higher compared to values for other inclusions. Overall, the inclusion of rubber particles led to a decrease in initial stiffness, improved ductility and strain hardening in specimens subject to compressive load. However, in comparison with the ductile behaviour of fibre-reinforced soil under tensile loads, granulates were found to be ineffective in changing the soil's brittle behaviour.