Investigation of the effect of using waste tire pieces as aggregate in geopolymer mortar production

In this thesis study, the potential for using plastic waste as raw material in the alternative production of construction materials in geopolymer mortars, which are an alternative to cement-based concrete production and have less environmental impact, was evaluated. The combined use of geopolymer-based mixtures containing industrial waste materials such as plastic waste (particles obtained from ground scrap vehicle tires) and slag (obtained as waste from ferrochrome plants), as well as fly ash (obtained as waste from thermal power plants), at different ratios has been investigated. The aim of the study is to produce composite geopolymer-based materials that are both environmentally sustainable and technically sufficient in terms of performance. In the experimental study, although the production was based on geopolymers in the mixtures, waste rubber particles (WRP) were used as filler in the matrix instead of aggregate in volumes of 1/4 . 1/3 and 1/2 by volume, with different binder mortars (cement alone, geopolymer alone, slag alone, fly ash alone, and their substitutes with cement) to prepare a total of 22 different mixtures. The compressive strength, flexural strength, and ultrasonic pulse velocity (UPV) values of the mixtures at 3. 7. 28 and 180 days were determined, and their mechanical and physical performances were compared and evaluated. SEM, EDX, FTIR, and XRD analyses were performed on samples taken from the specimens to evaluate their microstructures. The results indicate that the use of GEAAL in the cement matrix significantly reduces the mechanical properties of the cement matrix. On the other hand, it was observed that this negative effect could be significantly reduced by producing geopolymer mortars with certain proportions of cement added along with pozzolanic materials such as slag or fly ash. In particular, geopolymer mortars containing 1/4 GEAAL by volume, mixtures containing 90–95% slag or fly ash and 5–10% cement (M6. M7. M15. M16) have yielded the most successful results in terms of both strength and sustainability. When GEAAL is included in the mixture, particularly at a ratio of 1/2 . significant decreases in both compressive and flexural strength have been observed. In this context, the study demonstrates that it is possible to use plastic waste in construction materials, particularly in environmentally friendly geopolymer mortar applications, and that when supported by appropriate binding systems, it offers an important alternative for minimizing the damage to the ecosystem caused by cement production, primarily through the utilization of environmental waste.