混杂纤维对C60HPC高温后劈拉强度及超声声速的影响

Influence of hybrid fiber on tensile strength and ultrasonic velocity of C60HPC after high temperature

为了改善高强高性能混凝土的脆性及高温性能,将钢纤维与聚丙烯纤维混杂掺入C60HPC,研究其对混凝土劈拉强度以及超声声速的影响。设计了素混凝土、混掺钢纤维(体积掺量1.0%)和聚丙烯纤维(体积掺量0、0.1%、0.2%)组合的4种C60HPC,制作标准立方体试件由行高温(20~700℃)试验,测试混凝土试件的劈拉强度及超声波速,分析其随受火温度的变化规律。结果表明:C60HPC试件的劈拉强度及超声声速均随受火温度的升高基本均呈线性降低趋势;相同受火温度作用后,掺钢纤维的HPC较素混凝土劈拉强度及超声波速均有明显提高,混掺钢纤维和聚丙烯纤维混凝土较素混凝土的劈拉强度及超声波速有进一步提高,混掺纤维有利于改善高强高性能混凝土的脆性及高温性能,最优混掺组合为1.0%钢纤维和0.2%聚丙烯纤维。

Inorder to improve the brittleness and high temperature performance of high-strength and high-performance concrete,steel fiber and polypropylene fiber were mixed into C60 HPC to study its influence on concrete tensile strength and ultrasonic sound velocity.Four kinds of C60 HPCs of plain concrete,mixed steel fiber(1.0%by volume)and polypropylene fiber(0,0.1%,0.2%by volume)were designed to produce standard cube specimens for high temperature(20~700℃)test,the tensile strength and ultrasonic velocity of concrete specimens were tested,and the variation law of them with the temperature of the fire was analyzed.The results showed that the tensile strength and ultrasonic sound velocity of C60 HPC specimens decrease linearly with the increase of fire temperature.After the same fire temperature,the HPC with steel fiber is higher than the plain concrete in tensile strength and ultrasonic velocity.The tensile strength and ultrasonic speed of steel fiber concrete and polypropylene fiber concrete are further improved compared with the plain concrete.The blended fiber is beneficial for improving the brittleness and high temperature performance of the high strength and high performance concrete.The optimal blending composition is 1.0%steel fiber and 0.2%polypropylene fiber.