Effect of size variation of fibre-shaped waste tyre rubber as fine aggregate on the ductility of self-compacting concrete

Abandoning shredded waste tyre rubber (WTR) in cement-based mixes facilitates safe waste tyre disposal and conserves the natural resources used in construction materials. The engineering properties of such environment-friendly materials needed to be evaluated for field applications. This study examined integrating WTR fibre on microstructural, static load, and ductility properties of self-compacting concrete (SCC). The WTR fibre of 0.60-1.18-, 1.18-2.36-, and 2.36-4.75-mm sizes was used as fine aggregate at 10%, 20%, and 30% replacement levels. Microstructural characterisation of hardened concrete specimens was done by scanning electron microscopy. The compressive strength and static modulus of elasticity tests were used to examine static load resistance, while drop weight and rebound impact tests were used to investigate impact load resistance. The water permeability test was performed as a measure of the durability of SCC with WTR fibre. Relationships have been studied between dynamic MOE and impact tests and rebound and drop weight impact testing. The Weibull two-parameter distribution was used to analyse the drop weight test statically. The results show that WTR fibre size variations efficiently lowered the concrete stiffness reducing the brittleness. Furthermore, incorporating WTR fibre improved the impact resistance of SCC.