Assessment of Waste Polyethylene Terephthalate (PET) as Sand in Sustainable Geopolymer Concrete: Non-destructive Tests Investigation

The utilization of waste plastic and clay brick in geopolymer concrete will protect the environment, reduced carbon dioxide (CO2) emission and preservation of raw materials. This paper aims to evaluate the substitution of natural fine aggregate with shredded polyethylene terephthalate (PET) waste on some properties of geopolymer concrete based on blended (50:50)wt% metakaolin (Mk) and waste brick powder (WBP). Toward that end, four geopolymer concrete mixtures were prepared; three mixtures containing PET aggregate as sand replacement by volumetric levels (10%, 15% and 20%), and one mixture without PET aggregate as control mixture for comparison. Some non-destructive tests have been made to examine the influence of PET particles on the voids content; ultrasonic pulse velocity (UPV) and dynamic modulus of elasticity (Ed) to all geopolymer concrete mixtures at 7 and 28 days. Results indicated that inclusion of PET particles as fine aggregate could yield smaller voids content, higher pulse velocity and improved dynamic modulus of blended Mk-WBP geopolymer concrete. However, the mixture of 20% PET aggregate accorded the lowest voids content (8.90%) and higher UPV (4.444 km/s), while the 10% PET aggregate provided the optimum dynamic modulus of elasticity (28.41 GPa). This research could support the waste management and upgrade of sustainable geopolymer concrete for wide civil engineering applications.