Recycled polymer shot as sustainable additive for concrete: Mechanical, thermal, and environmental assessment

The exponential growth of plastic production has led to a dramatic increase in plastic waste, creating significant environmental and public health challenges. Among the available disposal methods, recycling is widely regarded as the most environmentally and economically advantageous. The development of effective strategies for recycling plastic waste is therefore a critical area of research, particularly in the construction industry. Incorporating plastic waste into concrete not only minimizes landfill disposal, but also has the potential to improve the performance of the material. This study investigates the effect of recycled polymer shot, incorporated at levels of 5% and 10% by cement mass, on the physical, mechanical, and microstructural properties of concrete. Comprehensive tests were performed, including measurements of density, thermal conductivity, slump, slip resistance, compressive, flexural, and tensile strength, as well as elastic modulus. The results demonstrate that the use of polymer shot significantly improves key properties of concrete, with increases of up to 45% in flexural strength and 62% in tensile strength at the higher addition level. Image-based microstructural analysis further revealed modifications in porosity and fracture surface complexity, supporting the observed performance enhancements. Overall, the incorporation of recycled polymer shot in concrete provides a promising approach for valorizing plastic waste, improving concrete performance, and supporting sustainable construction and resource management strategies.