Production of Recycled Plastic Aggregates and Its Utilization in Concrete

Abstract

Plastic represents an environmental issue, as only 7% of it is recycled. The plastic remaining is either burned, disposed of in an uncontrolled manner, or landfilled. Thus, to reduce the quantity of plastic that is disposed of, there is a need to increase the amount of the material that enters various product streams. This includes its use in the construction industry, and more particularly in concrete, which uses large quantities of aggregate. A novel aggregate (RPA) comprising recycled plastic was developed. The aggregate produced was lightweight, with a density ranging from 510 to 750k kg/m3 and absorption of from 2.7 to 9.81%. Other properties were comparable to aggregates of similar densities. Various composition RPA was used in concrete, and the resulting properties of both fresh and cured concrete were measured. For a given water to cement (w/c) ratio, it was possible to achieve slump of between 40 and 220 mm and fresh density of between 1,827 and 2,055 kg/m3. Further, 28-day strengths of between 14 and 18 MPa were achieved. Flexural strength was also measured. SEM analysis was undertaken to view the structure of the aggregate and the interface between the RPA and the cement matrix.