Physical and mechanical properties of concrete containing PET wastes as a partial replacement for fine aggregates

Abstract

In this study, the influence of using polyethylene terephthalate (PET) wastes as a partial replacement of natural sand is investigated to study the mechanical and physical properties of concrete. Fine aggregate (sand) is partially replaced by equivalent weight percentages of PET waste particles while maintaining all other proportions. Mechanical tests for compression, splitting, flexure, modulus of elasticity, energy absorption, and axial strain as well as physical tests for density, shrinkage, and absorption, are performed. In addition, the ultrasonic pulse velocity is presented. All specimens are observed for 7, 14, and 28 days. The tests results presented that the presence of PET particles changed the physical and mechanical properties of produced concretes. Physical properties (density and ultra sound velocity) gradually decreased as PET ratios increased, while an increase in absorption rate was observed. Furthermore, for strength-related properties, the results showed that the specimens containing partial substitution ratios ranging within 5 %–12.5 % displayed 26.8 %–43.64 %, 18.6 %–26.9 %, and 18.1 %–30.2 % increments in the compressive, tensile, and flexural strengths, respectively, compared with the reference specimens. The findings also revealed an increase in energy absorption and axial strain of the specimens with 5%–20 % replacement percentages, while the modulus of elasticity decreased as the PET content increased. The results further indicated that the strength parameters decrease when the PET content exceeds 15 %. In conclusion, replacing sand with waste PET particles positively affects the strength-related values of concrete specimens as long as the replacement ratio is less than 15 %.