Effect of Recycled Coarse Aggregates (RCA) on Geo-Polymer-Based Concrete

The construction industries are looking towards the production of environmentally friendly concrete, with the use of fewer natural resources, less energy, and minimum carbon dioxide emissions. For this reason, the geo-polymer concrete is one of the best options. The concrete produced with a polymerization process; a reaction between alkaline compounds containing alumina and silica; is called geo-polymer-based concrete. This study is focused on investigating the density and strength properties of geo-polymer concrete with Recycled Coarse Aggregates (RCA). Three mixes were designed with 0%, 50%, and 100% RCA with a fixed water-binder ratio equal to 0.4. The results revealed that the compressive, tensile, and flexural strength of geo-polymer-based concrete with RCA reduced and depended on the percentage of RCA used. The flexural performance of the concrete was observed better compared to compressive and tensile strength. However, the density of concrete is decreased by approximately 14% with the addition of RCA resulting in lighter concrete than the control mix.