超高泵送钢纤维混凝土的初裂强度和弯曲韧性

Initial Strength and Flexural Toughness of Steel Fiber Reinforced Concrete with Super-high Vertical Pumping Distance

参照美国材料与试验协会(ASTM)试验方法,对满足超高距离泵送要求且抗裂性能优异的纤维混凝土的初裂强度和弯曲韧性进行了研究。借助弯曲荷载-挠度全曲线,分析了纤维掺量和类型对韧性指数和初裂荷载的影响。结果表明,钢纤维混凝土的抗弯初裂强度、极限强度和弯曲韧性均随纤维掺量的增大而提高。其中,纤维体积率为0.8%,泵送高度达306 m的钢纤维混凝土的初裂强度和极限强度比基准混凝土分别提高了15.6%和31.4%,韧性指数I5提高5.22倍,I10提高8.7倍,I20提高12.39倍。

According to the testing method of ASTM, the initial cracking strength and flexural toughness of steel fiber reinforced concrete （SFRC）, which fulfilled the need of pumping with super-high vertical distance and increased markedly the ability to resist cracking of concrete, were analyzed. Through the load-deflection curves of SFRC, the effects of fiber kinds and fiber content on the first-crack strength and the flexural toughness of SFRC were contrasted with those of concrete. The experimental results showed that the first-crack strength, ultimate flexural strength and flexural toughness of SFRC could be increased with fiber volume fraction. It was also indicated that not only the first-crack strength and ultimate flexural strength of the SFRC with fiber volume fraction 0.8%, which could be pumped to 306 m, can be enhanced by 15.6% and 31.4% respectivdy, but also the index of flexural toughness, and can be increased more than 5.22, 8.7 and 12.39 times respectively compared with normal concrete.