Physico-mechanical, microstructural and dynamic properties of newly developed artificial fly ash based lightweight aggregate – Rubber concrete composite

The use of industrial by-products in concrete would increase the sustainability of the construction industry. In this study, the potential use of scrap crumb rubber as fine aggregate in lightweight (Lytag) concrete was experimentally investigated. The effects of replacing natural sand by crumb rubber particles on the physico-mechanical, micro-structural and dynamic properties of the Lytag concrete were evaluated. When the rubber was introduced, the reduction in compressive strength of the Lytag concrete was experienced due to the less than perfect bond between the cement paste and the rubber as confirmed by the micro-structural observation. Additionally, there was flocculation of some of the crumb rubber particles and the packing of the rubber particles contributed to pockets of voids resulted in anisotropy in the concrete. The results also showed that the rubber not only meliorated the resistance of the cementitious Lytag composite to cracking from impact load but overall impact strength was also improved as the rubber particles acted as impedance to crack initiation and propagation.