Compressive mechanical properties of cement mortar containing recycled high-density polyethylene aggregates: Stress–strain relationship

Abstract

This study contributes to the understanding of the effect of recycled high-density polyethylene (HDPE) aggregates on the compressive mechanical properties and stress–strain relationship of cement mortar. HDPE aggregates recycled from plastic wastes were used to substitute natural sand in cement mortar, thereby offering a novel approach to plastic waste management and reducing the overconsumption of limited natural resources. The compressive behavior of cement mortar containing 0–100% HDPE contents was investigated after 7 and 28 days. The experimental results showed the negative effect of HDPE aggregates on the modulus of elasticity (Ec) and compressive strength (fcmax) of cement mortar. However, the substitution of natural sand with HDPE aggregates reduced the density and increased the axial deformation capability of cement mortar, particularly when the volumetric substitution percentage exceeded 50%. The Ec, peak strain, and ultimate strain exhibited strong relationships with the substitution percentage and fcmax. Furthermore, the proposed empirical relationships between the parameters were evaluated. Finally, stress–strain models of HDPE mortars were established based on the available models for concrete. The proposed models appropriately predicted the complete stress–strain curves of cement mortars containing various amounts of plastic content.