| 요약2 |
This study investigated the fire resistance performance of high performance concrete containing polypropylene fiber(PP) and poly vinyl alcohol fiber(PVA) after 3 hours unstressed fire test. Test showed that increase of fiber contents decreased fluidity of specimens. Although PVA has been well known as a hydrophile properties material, specimens adding it exhibited lower fluidity than concrete adding PP, due to bigger aspect ratio of PVA. Compressive strength of specimens containing PP or PVA was indicated at similar value to control concrete. These results represented that the compressive strength of concrete was not affected by fiber adding ratio. However, at 28 days, compressive strength of all specimens showed more than 50MPa, regardless of fiber contents. In addition, temperature history test for control concrete and PP fiber composite concrete was carried out. Temperature rising rate of both specimens was becoming decreased in certain time, due to addition of fiber and thermal properties of concrete components. After that the increasing rate of temperature was continually proportional, then the highest value of stirrup ambient temperature was indicated at 500°C in 180 minutes, regardless of fiber contents. Meanwhile, specimens adding PP more than 0.1vol% prevented spalling occurrence, regardless of specimen size. However concrete containing PVA which was conducted by 100×100×200mm cylinder size, exhibited partly spalling occurrence and it protected spalling in mock-up size. Weight reducing ratio of control concrete was indicated at 22% and that of other fiber adding specimens was 7～8%. All specimens, regardless fiber type and contents, showed that residual compressive strength ratio was 65 to 80% range. |