Production of Green Synthetic Lightweight Aggregate and its Utilisation in Green Concrete

Environmental sustainability faces many challenges, including the increase in the amount of plastic compared to its low recycling rate. Therefore, it is important to increase its recycling rate by using plastic waste in other applications such as aggregate and/or concrete production, its recycling rate can be increased, while reducing its negative effects and saving natural resources. A green synthetic lightweight aggregate (GSLA) containing plastic waste and additives was produced, and its physical and mechanical properties were compared with those of control aggregates. A green lightweight concrete comprising GSLAs was then developed, and their fresh, hardened and microscopic properties were investigated and compared to those of reference mixes. Findings showed that the GSLAs were light in weight, with an average specific gravity of 1.7 and less water absorption at around 0.8%; it was stiff with an average impact value of 16%. Green lightweight concrete mixes with average slump of 170 mm and density of 1900 kg/m³ were feasibly produced. Additionally, average of 28-day compressive and flexural strengths of the produced concrete was only 16% and 40% less, respectively, compared to the normal weight control mix. The SEM analysis indicated strong interlocking between the cement paste and the developed aggregates.