Promoting Circular Economy in Cementitious Materials: Per-Formance of Cementitious Materials Incorporating Synthesized Composite Aggregates from Recycled Plastic Waste

It is widely acknowledged that beverage consumption generates significant amounts of non-biodegradable polyethylene terephthalate (PET) bottle waste. It was shown that these wastes could be effectively incorporated into mortars for the construction of cleaner green buildings. The present work aims to study the properties of a mixture of silica sand and shredded PET bottles that were subjected to thermal treatment. The final product obtained, i.e. lightweight synthesized sand (LSS), is intended to replace natural sand in volume, at rates of 25%, 50%, 75% and 100%. In addition, a series of destructive, non-destructive, and durability tests were carried out on the obtained waste plastic synthetic sand (WPSS) composite mortar. The results showed that high LSS percentages increase the thermal effi-ciency of the composite mortar but reduce their density. In particular, there was a 23% re-duction for composite WPSS100. On the other hand, it was found the dynamic modulus of elasticity of this composite mortar decreased by 70%. Moreover, no alkali-silica reaction (ASR) was detected. In addition, the mortar samples incorporating 25% LSS satisfied the minimum standards for compressive strength. Based on the above, it can then be con-cluded that the integration of these composites in the construction of sustainable build-ings may represent an effective and sustainable solution for judicious management of plastic waste, significant reduction of CO₂ emissions, and effective promotion of circular economy.