The effects of high temprature on the mechanical properties of polymer-based synthetic micro fiber reinforced mortars

In this thesis, the behavior of mortar, produced by adding polymer-based synthetic micro fibers, is investigated at elevated temperatures. Mortar specimens were produced by addition of fibers to the mix at 0%, 0.5%, 1% and 1.5% percentages, and silica fume was used at 0%, 5%, 10% and 15% percentages as a replacement of cement by weight. After standard curing, reference mortar specimens were kept in laboratory condition, and others were subjected to the temperatures of 300 oC, 600 oC and 900 oC. Then, specimens subjected to high temperatures left to self-cooling. In order to determine the physical properties such as dry unit weight, void ratio, water absorption and ultrasound tests were made on mortar specimens after cooling. Besides, flexural and compression tests were made for the mechanical strengths of mortars. After application of high temperatures, it was observed that dry unit weight and ultrasound pulse velocity of mortar specimens decreased, however void ratio and water absorption of mortars including fiber and silica fume were increased less than reference specimens. The mechanical strengths of mortar increased by increasing silica fume and fiber before application of high temperature. On the other hand, mortars had good performance to the high temperature depending on the silica fume and the synthetic micro fiber the contents.