Combined Effects of Densified Polystyrene and Unprocessed Fly Ash on Concrete Engineering Properties

The present study evaluated the combined effects of two types of waste materials of expanded polystyrene (EPS) and unprocessed fly ash (FA) on different properties of concrete. A novel recycling technique of densifying waste EPS is used to produce a novel lightweight aggregate (LWA). This new technique has solved the problem of segregation in concrete by coating EPS particles with a natural binder of clay and cement. Nine different concrete mixtures with a water to cement ratio of 0.8 were used. The densified EPS and unprocessed FA were partially replaced with natural aggregate and Portland cement, respectively. The engineering properties, including workability, density, compressive strength, ultrasonic pulse velocity (UPV), and water absorption (WA) were investigated at different curing times. According to the experimental results, there is a decrease in compressive strength and UPV with increasing this novel LWA content in concrete. However, by using a suitable mix design, the utilisation of these two waste materials in concrete using an appropriate recycling technique is possible.