Novel lightweight concrete containing manufactured plastic aggregate

Plastic waste and its low recycling rate make a significant contribution towards the pollution of the environment. It is therefore essential that plastic waste is utilised in different applications, such as aggregates in concrete. In this paper, an investigation of a manufactured plastic aggregate as a replacement for pumice lightweight aggregate and Lytag aggregate in concrete is presented. The influence of replacement level on the fresh, hardened and microstructure properties of concrete was investigated. The slump, compressive strength, flexural strength, splitting tensile strength and elastic modulus decreased with the increase in replacement level. Neither the fresh density nor the hardened density was significantly affected by replacement level. The Lytag and conventional lightweight concrete mixes had a brittle failure; whereas the concrete mixes incorporating the manufactured plastic aggregate had a ductile post-peak behaviour. The results suggest that the concrete mix containing the manufactured plastic aggregate at a replacement level of 25% can be used in structural and non-structural applications requiring moderate strength and ductility. Predictive models were proposed and demonstrated to be in good agreement with the experimental results for the mechanical properties of the concrete mixes incorporating the manufactured plastic aggregate.