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冻融破坏是混凝土耐久性的重要病害之一,严重影响混凝土结构的使用寿命。本试验研究了C50高强度混凝土抗冻性能随纤维素纤维掺量的变化规律,探讨了纤维素纤维改善混凝土抗冻性能的机理。试验结果表明:掺加纤维素纤维可以明显改善混凝土的抗冻性能,随着冻融次数的增加,纤维的作用愈加明显;300次冻融循环后,素混凝土的相对动弹性模量降为42.46%,而纤维混凝土试件U1、U2、U3和U4的相对动弹性模量分别为68.21%、67.42%、68.32%和70.17%。纤维掺量为0.9~1.5 kg/m3时,纤维素纤维混凝土抗冻标号均大于D300。对于抗冻指标要求高的地区和结构,选用纤维掺量1.3 kg/m3比较经济合理。
Freeze-thaw damage is one of the important diseases of concrete durability, seriously affecting the service life of concrete structures. The experiment studied the variation of frost resistance of C50 high strength concrete with the content of cellulose fiber, and discussed the mechanism of cellulose fiber to improve frost resistance of concrete. The experimental results show that the cellulose fibers can significantly improve the frost resistance of concrete, and the effect of fibers becomes more obvious with the increase of the number of freeze-thaw cycles. After 300 freeze-thaw cycles, the relative dynamic elastic modulus of concrete decreases to 42.46 %, While the relative dynamic elastic modulus of fiber concrete specimens U1, U2, U3 and U4 are respectively 68.21%, 67.42%, 68.32% and 70.17%. Fiber content of 0.9 ~ 1.5 kg / m3, the cellulose fiber concrete antifreeze label were greater than the D300. Frost resistance indicators for the high demand areas and structures, the choice of fiber content of 1.3 kg / m3 more economical and reasonable.