Engineering and sustainability characteristics of concrete blended with waste rubber crumbs as an alternate to conventional coarse aggregate

Present study examines the performance of concrete blended with waste shredded rubber (WSR) as an alternate to conventional coarse aggregate. Six different mixes were developed: one control concrete, with 100% made up of conventional natural resources and five mixes were developed by altering the proportion of WSR from 10%, 20%, 30%, 40% and 50%. The physical, mechanical and sustainability performance of the concrete samples were examined in detail. In addition, the behavior of concrete under the influence of fire temperature with WSR was also examined in detail. The specimens were subjected to a temperature of 200, 400, 600, and 800 °C following ISO 834 standard time-temperature curve. The physical changes, surface modification, mass loss, porosity, residual strength was examined in detail and the same was compared with the control concrete values obtained prior to temperature exposure. The concrete developed with WSR possess larger strength variation before heating, showing that the WSR had a direct influence on the strength of the mix. For the initial replacement levels, 25% loss was seen, whereas partial replacement of conventional coarse aggregate with WSR possesses 77% loss. After subjecting to 200 °C, marginal variation in strength was seen, whereas after subjecting to 400 °C, the loss was pronounced, for the mix with 50% WSR, the loss was seen to be 33%. Moreover, after subjecting to 600 °C, 50–60% strength loss was seen for the higher proportions of WSR. After 800 °C, the concrete samples with WSR tends to collapse without taking any load. In the case of sustainability point of view, higher the proportions of WSR lower will be the cost of production, embodied carbon and energy requirement.