Recovery of Plastic Waste in the Production of Industrial Sludge-Based Geopolymer Mortars

Abstract

The purpose of this research study is to produce a geopolymer mortar with a lower environmental impact, to recycle polyethylene terephthalate (PET) plastic waste, and study the possibility of using PET particles as a substitute for sand by replacing and using calcined industrial sludge as a precursor in mortar production. A study of the geopolymer mortars revealed a chemical and mineralogical composition and mechanically compatible with that of a control geopolymer mortar, defined as a mortar with no plastic added to the geopolymer paste. The industrial sludge precursors revealed the presence of (Quartz and Muscovite) two crystalline phases. The FTIR spectra of the geopolymer slurries showed the presence of Si-O-T, with this absorption band shifting to lower frequencies when PET particles were added to the slurry. We also analyzed SEM images of some samples. The compressive strength and flexural strength of the mortar showed a decrease with an increase in PET particles as an alternative to sand. Geopolymer mortars formulated with recycled plastic as a sand alternative displayed mechanical performance approaching that of sand-based mortars. These findings collectively suggest the viability of utilizing plastic waste as a raw material for geopolymer mortar production.