Recycled waste glass as fine aggregate in eco-friendly gypsum-cement composite

Abstract

The development of eco-friendly construction materials in the construction industry is an effective approach to realizing sustainability. One of the waste materials that can be utilized for this purpose is waste glass. Recycling waste glass into a construction material not only can consume fewer natural resources but also can reduce greenhouse emissions. Many studies have shown that it is feasible to incorporate waste glass (WG) as cementitious material or aggregate in cement-based materials, but limited research had paid attention to its application in gypsum-cement composite (GCC). Accordingly, this study is aimed to investigate the effect of the addition of recycled waste glass (RWG) from beverage bottles on the mechanical properties and water-resistant performance of GCC. The milled WG was incorporated as fine aggregate (less than 0.6 mm) in GCC at a ratio of 0%, 10%, 30%, 50%, 70%, and 100% by weight of the binder. The properties of GCC containing RWG in terms of consistency, bulk density, compressive strength, and water-resistant performance were assessed. The consistency was found to decrease by RWG due to increased water demand for wetting its surface. Owing to the higher density of RWG, the bulk density was observed to increase from 1670 kg/m3 to 1963 kg/m3 with higher amounts of RWG. The RWG addition also had positive effects on the mechanical strength where it can significantly improve the compressive strength (by up to 26.9%) of GCC, attributed to its pozzolanic reaction and filler effect. Besides that, the water absorption showed a downward tendency with an increment of RWG content (from 9.8% to 3.1%) while the softening coefficient increased by 52.6% to reach 1.16, suggesting good water resistance of the produced GCC. Based on the above findings, RWG has the potential to enhance the mechanical properties and water-resistant performance of an eco-friendly GCC, thus providing an alternative avenue to reuse the RWG.