## 3 Results and Discussion
### Flexural Strength and Flexural Toughness  
Figure 7 shows the flexural strength test results before and after high temperature exposure of the steel fiber reinforced cement composites with polymer. The flexural strength at 1.0% polymer contained the highest strength of 53.8 MPa, and the flexural strength at 0.5% was 47.0 MPa. The flexural strength at 1.5% was 49.1 MPa before high temperature exposure. The bending strength change level with respect to the polymer content was insignificant when compared with 0% polymer content. Thus, the flexural strength was reduced by 40-50% compared to the flexural strength before high temperature exposure, and the flexural strength was superior to that of general concrete. The resistance against bending is improved, owing to high mixing of the steel fibers. At 1.0% polymer contain the flexural strength was 26.3 MPa, whereas at 1.5% was 21.8 MPa after exposure to high temperature. Figure 7 shows a decreased in flexural strength of SIRRCCs after exposure to high temperatures. Increasing the polymer contain can decrease the flexural strength of SIRRCCs after exposure to high temperature. The steel fibers were effective in reducing the degradation of flexural strength of the concrete after exposure to the high temperatures. After exposure to high temperature, the flexural behavior decreases in flexural strength due to the interaction of the high-mixed steel fibers and polymer in the cement mortar. There is a greater chance of decreasing the strength of concrete if exposed to high temperature because of the passing of free water through pores created by the melting of polymer.  
Figure 8 shows the flexural toughness test results before and after high temperature exposure. A large energy absorption capacity of 1553 N-m is observed for 1.0% polymer content before high temperature exposure. This is because the high-strength steel fiber of SIRRCCs transfers to the crack surface and, thus, the toughness and energy absorption capacity are increased by absorbing energy through the process of degrading adhesion or drawing out the steel fiber. The flexural toughness test after high temperature exposure showed approximately 50% lower flexural toughness than that before high temperature exposure. When compared to 0% polymer content, the decrease in flexural toughness after high temperature is minimal; however, at 1.5% polymer content, there is a larger difference than that with other variables, because more voids are created on the specimen, owing to the high temperature [18]. From Figure 8, the toughness was 697 N.m when 1.0% polymer was added  
Figure 6: Compressive strength before and after high temperature exposure with polymer content (%).  
during mixing, whereas 645 N.m at 1.5% was found after exposure to high temperature. Figure 8 shows a decrease in the toughness of SIFRCCs after exposure to high temperatures.  
The SIFRCCs exposed to high temperature the water inside the element will evaporate and a part of it will flow out of the SIFRCCs. Other part will flow inside the porous medium, depending on the permeability of the materials. SIFRCCs lose more strength if moisture is not permitted to escape when exposure to high temperature due to the increase in internal vapor pressure. The addition of polymer improved spalling, which can melt during high temperature and create channels to alleviate internal vapor pressure.