Performance of Geopolymer Mortar Containing PVC Plastic Waste from Bottle Labels at Normal and Elevated Temperatures

Abstract

This work focused on reusing polyvinyl chloride (PVC) plastic waste from bottle labels (BLWA) as lightweight aggregates in geopolymer mortar. This way of reusing plastic waste is beneficial for diminishing the negative impacts of plastics on the environment and reducing CO2 emissions by using geopolymer as an alternative cementing material. BLWA was used to partially substitute natural fine aggregate at ratios of 0, 5, 10, 15, and 20% by volume. The geopolymer mortar properties were tested, and the durability after exposure to elevated temperatures was also assessed. It was found that the strengths were adversely affected by increasing BLWA content. The water absorption and porosity were also increased with beneficial benefits on the reduced density (9–17%) and thermal conductivity (28–44%). The geopolymer mortar containing 5–15% BLWA satisfied the requirement of a lightweight mortar used in masonry work. After exposure to temperatures up to 600 °C, the properties of geopolymer mortar containing BLWA reduced more than that of the control mortar due to the thermal degradation of BLWA at high temperatures. However, when increasing the temperature from 600 °C to 900 °C, there was no further loss in strength. Microstructure analysis indicated that increasing temperatures caused more increased voids and microcracks in geopolymer mortars, especially the ones containing BLWA. However, after exposure at 900 °C, these voids and cracks were minimized at 900 °C due to sintering effects. The findings in this work confirmed the feasibility of using this PVC waste derived to produce lightweight construction material with thermal insulation properties.