Transforming waste into strength: Evaluating properties of concrete with waste glass substitution

Abstract

Waste glass (WG) poses a significant environmental challenge due to its non-biodegradability and prevalence in landfills. This paper investigates the effects of using WG as a replacement for coarse aggregate (CA), fine aggregate (FA), and cement in concrete, utilizing WG coarse aggregate (WGCA), WG fine aggregate (WGFA), and WG powder (WGP), respectively. WG was mechanically crushed and sieved to obtain WGCA, WGFA, and WGP. The use of whole crushed waste glass (WG) particles, without any residue, introduces a novel aspect to this work. The study examined these replacements in a control concrete mix with a water-cement ratio of 0.38 and a mix proportion of cement, FA, and CA of 1:1.717:2.560 by weight. Replacement levels were set at 0 %, 5 %, 10 %, 15 %, 20 %, and 25 % by weight of the respective ingredient. Results showed that incorporating WG improved the slump value of the concrete while slightly decreasing its density. The optimum replacement levels were identified as 15 % for both WGCA and WGFA, and 10 % for WGP, which enhanced the 28-day compressive strength by 22.1 %, 20.1 %, and 13.1 %, respectively. At 20 % replacement for CA and FA, and 15 % for C, the compressive strength was comparable to that of the control concrete. The elastic modulus followed a similar trend to the compressive strength. However, at these optimum WG replacement levels, flexural strength decreased to 6.04 MPa, 5.89 MPa, and 6.14 MPa, respectively, from 6.32 MPa in the control concrete. Splitting tensile strength decreased to 2.97 MPa, 3.07 MPa, and 3.23 MPa, respectively, from 3.35 MPa. Water absorption also reduced to 3.83 %, 4.23 %, and 4.41 %, respectively, from 4.61 %. Empirical models were developed and compared with those from previous studies. Further research to strengthen the interfacial transition zone and ascertain detailed durability properties is necessary before implementing this sustainable concrete in real-world applications. The implementation of the results from this research may not only minimize glass waste but also contribute to the production of sustainable concrete, reducing CO₂ emissions and mitigating environmental degradation by lowering the consumption of cement and aggregates. Furthermore, this work plays a significant role in global efforts to reduce solid waste and combat environmental pollution.