大流动度混杂纤维增强混凝土耐久性试验研究

Experimental Research on Durability of Hybrid Fiber Reinforced Concrete with High Fluidity

在纤维总体积掺率不超过1%的情况下,采用钢纤维、塑钢纤维及聚丙烯纤维单掺、双掺和三掺配制得到高流动度纤维增强混凝土。通过稠度试验、基本力学性能试验以及耐久性试验,对比分析了纤维混杂方式和纤维混掺比例对基体混凝土工作性能、基本力学性能以及耐久性的影响。结果表明,钢纤维/塑钢纤维/聚丙烯三元混杂可有效改善基体混凝土的抗压强度和劈裂强度,最大分别提高了25%和32.61%;大流动度混杂纤维增强混凝土的抗渗等级可满足P8要求,具有良好的抗渗性能,最大渗水高度仅为29mm;大流动度混杂纤维增强混凝土的抗冻等级可满足F250要求,且前175次冻融循环质量损失率维持在1%~2%;基于工作性能、基本力学性能以及耐久性最优的混掺比例为0.4%SF、0.4%HF、0.11%PPF。

With the total volume fraction of fibers below 1.1%, the fiber reinforced concrete with high fluidity is prepared by adding steel fiber, steel fiber and polypropylene fiber single, double or triple. Experiment on mechanical properties, frost-resistance and impermeability of hybrid reinforced concrete were carried out. Based on the test results, the effect of fiber volume fraction and hybrid mode upon the mechanical property and durability of the HFRC are analyzed. The results show that SF/HF/PPF HFRC can significantly improve the compressive strength and splitting strength of the matrix concrete with largely 25% and 32.61% respectively. The fiber reinforced concrete with high fluidity owns wonderful impervious performance and it can meet the requirements of P8 with the minimum penetration height of 29mm. The fiber reinforced concrete with high fluidity owns wonderful anti-freezing property and it can meet the requirements of F250. And the mass loss rate of 175 freeze-thaw cycles is only 1%-2%. On the basis of the working performance, mechanical property and durability, the most suitable fibers proportion of CF60 is 0.4%SF, 0.4%HF and 0.11% PPF.