| 요약2 |
This study investigate spalling resistance of high strength concrete in fire, focusing on polypropylene and nylon fiber content with different aspect ratios. Test showed that increase in fiber content decrease the fluidity of fresh concrete, but adding fiber below 150 aspect ratio exhibited favorable slum flow while adding more than 450 of aspect ratio decreased significantly the value. Although air content was tend to increase as aspect ratio of fiber increased, due to the decrease of the fluidity, but still satisfied the target value. The compressive strength of all specimens was indicated at around 60 to 80MPa, which is obviously in the range of high strength concrete, and tensile strength of specimens exhibited 7 to 9% of the compressive strength values. For the properties of spalling after fire test, adding below 1,000 of aspect ratio in fiber showed favorable spalling resistance. In addition, both NY-750 and 1,000 exhibited spalling protection even in only 0.05vol.% of fiber content. Overall, adding only 0.04vol.% of NY-750 had the most effective results when considered the properties of fluidity |