High temperature resistance of concretes with GGBFS, waste glass powder, and colemanite ore wastes after different cooling conditions

Residual strength of the concrete members after being exposed to high temperatures is very important for the structures. In this study, residual strengths of the concretes produced with ground granulated blast furnace slag (GGBFS), waste glass powder (GP), and colemanite ore wastes (CW) were investigated. GGBFS and GP were used with the ratios 10%, 20%, and 30%, CW was used 1%, 3%, and 5% by weight. These 28 and 90-day cured concretes were exposed to 200, 400, 600, 800, and 1000 °C for 1 h. After this high temperature treatment, the test samples were subjected to two different cooling regimes as water-cooling and air-cooling. The residual strength of the concretes was investigated by compressive strength tests. Besides, weight losses and ultrasonic pulse velocity results were investigated as well. Surface defects of the samples were examined by the image analyze method and microstructure of the samples were evaluated by Scanning Electron Microscope (SEM) imaging. According to the results, colemanite ore waste containing concretes exhibited better performances than other series. In addition, up to 600 °C water-cooled samples had higher residual strength. This was changed in favor of air-cooling samples after 600 °C.