Investigation of high temperature performance of fiber reinforced waste basalt powder based geopolymer mortars

In this thesis, mortar mixtures were created by activating basalt stone cutting waste with sodium silicate. The sodium silicate content in the mixtures was determined to contain 10% Na2O by weight of the basalt waste. In addition to fiber-free mixtures, fiber-reinforced geopolymer mortar mixtures containing 0.5% and 1.0% basalt or polypropylene fiber by volume have been manufactured. The produced mixtures were subjected to thermal curing at 100 ºC for 2 different periods: 8 hours and 24 hours. Basalt sand was used in mortar mixtures due to its heat resistance. Flexural and compressive strength tests were carried out on 7, 28 and 56 day old specimens obtained from mortar mixtures. The effects of thermal curing time and fiber content on the strength values of mortars were examined. Additionally, geopolymer mortars were separately exposed to 3 different temperatures: 600 ºC, 800 ºC and 1000 ºC. Flexural and compressive strength tests were carried out on the mortars after high-temperature exposure. Weight losses in mortars due to high temperature were also determined. In addition, XRD and SEM/EDX analyses were performed on the selected mortars to investigate the changes in the microstructure of the mortars due to high temperature. There was no loss of compressive strength in any of the mortars under the influence of 600 ºC, 800 ºC and 1000 ºC, and even a strength increase at different rates was observed compared to before the experiment. It has been observed that fiber-reinforced waste basalt powder-based geopolymer mortars are resistant to temperatures up to 1000 ºC.