Investigation of the effect of polymer-based waste on the physical and mechanical properties of cement-based materials

Polymer waste, which we use in various areas and places in our daily lives, poses a significant threat to the environment. The recycling and disposal of these wastes could be challenging and costly. In this regard, reuse plays an important role. Another product widely used worldwide is concrete, ranking second after water. Therefore, the environmental pollution and consuming the raw material sources resulting directly or indirectly from traditional concrete production have led to the exploration of alternative uses for various waste materials. The greatest threat in terms of environmental pollution is carbon emissions, which largely occur during cement production, aggregate production, and transportation. In this study, the use of polymer-based waste as an aggregate in cement-based mixtures was investigated as an alternative solution for both issues. The impact energy dissipation capacity, sound transmission properties, mechanical, and physical properties of the final product incorporating waste were examined and attempted to be improved. Firstly, a detailed performance study has been conducted to solve the rheology problems of plastic waste included mixtures and enable the use of a high amount of waste. Additionally, this study has facilitated the determination of the most suitable types of these wastes. After the performance study, the main studies have also resulted that the mixtures could be used for various industrial purposes because of their suitable properties. Firstly, it has been observed that lightweight mortar mixtures having weight per unit of volume as below than 2000 kg/m3 could be obtained with usage of 100% waste with enough workability. In terms of mechanical properties, it has been observed that mortars containing 100% polystyrene have higher toughness values than the control samples, and another mortar mixture containing 20% electrical cable waste and 80% polycarbonate waste has toughness values quite similar to the control sample. Mortar mixtures containing 100% polycarbonate and polystyrene have compressive strengths above 25 MPa. Furthermore, the addition of silica fume to all mixtures has shown positive effects on toughness, water absorption, and porosity. Moreover, mortar mixtures with 5% silica fume (as a cement replacement) and 100% polystyrene have exhibited higher sound reduction rates in areas with high noise levels, such as industries, compared to the control samples. In impact tests based on weight dropping, all mixtures containing varying amounts of polymer waste have outperformed the control samples. Increasing the amount of waste has even contributed to increased impact resistance and preservation of structural integrity. In conclusion, this study demonstrates that mortar mixtures containing polymer wastes could continue to be researched for the use in concrete barriers.