An experimental investigation of the mechanical characteristics and drying shrinkage of a single-size expanded polystyrene lightweight concrete reinforced with waste plastic fibres

Abstract

This research focuses on developing single-size expanded polystyrene (EPS) lightweight concrete reinforced with waste plastic fibres (WPFs) and evaluating its mechanical characteristics and drying shrinkage. An experimental investigation of two groups of concrete mixtures was conducted. The first experiment involved the partial substitution of the coarse aggregate volume with 5%, 10%, 15%, 20%, 25%, and 30% EPS beads. The second investigation involved six different volume fractions Vf of waste plastic fibres. A comprehensive test programme was implemented to evaluate these mixtures by measuring compressive strength, flexural strength, drying shrinkage, ultrasonic pulse velocity, and water absorption. The incorporation of EPS in the concrete mixtures in Group 1 resulted in reduced compressive strength and flexural strength at all ages. The drying shrinkage of the concretes in Group 1 increased with the proportion of EPS aggregate. The addition of waste plastic fibres to the concrete mixes in Group 2 improved the compressive strength for volumetric fractions of WPFs between 0% and 1%, but greater proportions of volumetric fibres up to 1.5% decreased the compressive strength. The inclusion of WPFs reduced the drying shrinkage of the Group 2 concretes at volume fractions between 0.25% and 1.25% compared to that of the reference mix (M8). In general, drying shrinkage developed rapidly in concrete specimens with added EPS and WPFs tested at 40–60 days and became more stable after 60 days.