The Impact of Differently Prepared Mixed Plastic Waste Granules on the Structure and Properties of Concrete

The relatively low production cost and short lifespan of plastic products contribute significantly to the annual accumulation of plastic waste, raising serious environmental concerns. Conventional disposal methods like landfill and incineration not only waste valuable resources but also result in substantial secondary pollution. In response to the imperatives of sustainable development and environmental protection, in this work, different preparation methods (mechanical processing; heating and covering with milled sand and glass; covering plastic granules with polymers and then mineral materials such as microsilica and waste metakaolin; using other chemical additives) for plastic granules from waste and their influence on the properties of cementitious materials were studied. Lightweight concrete properties such as density, ultrasound pulse velocity, flexural and compressive strength, water absorption, and the interaction zone between the cement matrix and plastic granules were analyzed. It was determined that one-third by volume of natural aggregate can be replaced with specially prepared plastic granules from waste, obtaining a bending strength of the lightweight concrete of about 5 MPa, a compressive strength at 28 days of approximately 30 to 35 MPa, a density of about 1850 kg/m³, and an ultrasound pulse velocity of 3900 m/s.