玄武岩-粗聚丙烯纤维干硬性混凝土拉压性能试验研究

混杂纤维增强干硬性混凝土在国内外已有广泛的应用,纤维配比是影响其拉压性能的主要因素之一。为研究玄武岩纤维与粗聚丙烯纤维配比对干硬性混凝土拉压性能的影响,将玄武岩纤维与粗聚丙烯纤维单掺或按不同比例混合掺入干硬性混凝土中,开展不同养护龄期下纤维混凝土的抗压、劈裂抗拉试验,分析纤维混杂增强效应,并基于成熟度理论修正养护龄期,优化玄武岩-粗聚丙烯纤维干硬性混凝土的劈裂抗拉强度预测模型。结果表明:玄武岩纤维与粗聚丙烯纤维的掺入不仅提升了干硬性混凝土抗压、劈裂抗拉性能,而且纤维的桥接作用能明显改善混凝土的脆性破坏特征,其中玄武岩纤维与粗聚丙烯纤维混掺配比为1 ∶2(质量比)时最为明显,表现出了最优的纤维混杂正效应。根据等效龄期-抗压强度关系式计算得到的混凝土抗压强度与劈裂抗拉强度具有更好的幂函数关系,该模型便于计算及预测不同养护温度条件下玄武岩-粗聚丙烯纤维干硬性混凝土的拉压性能。

Tensile and Compression Properties of Basalt-Coarse Polypropylene Fiber Reinforced Roller Compacted Concrete

Hybrid fiber reinforced roller compacted concrete has been widely used at home and abroad, the ratio of fiber content is one of the main factors affecting its tensile and compression properties. To study the effect of the mix proportion of basalt fiber and coarse polypropylene fiber on the tensile and compression properties of roller compacted concrete, basalt fiber and coarse polypropylene fiber were single doped or hybrid with different proportions into roller compacted concrete. The compressive and splitting tensile tests of fiber reinforced concrete at different curing ages were carried out, the hybrid reinforcing effect of basalt fiber and coarse polypropylene fiber were analyzed. The curing ages were modified based on the maturity theory, and the splitting tensile strength prediction model of basalt-coarse polypropylene fiber roller compacted concrete was optimized. The incorporation of basalt fiber and coarse polypropylene fiber not only improves the compressive and tensile properties of roller compacted concrete, but also optimizes the brittle failure characteristics and improves the toughness of concrete specimens due to the bridging effect of fibers, especially when the mass mixing proportion of basalt fiber and coarse polypropylene fiber is 1 ∶2, which shows the optimal positive fiber hybridization effect. The compressive strength calculated by the equivalent curing age-compressive strength equation has a better power function relationship with the splitting tensile strength, and the model is convenient to calculate and predict the compressive and tensile properties of basalt-coarse polypropylene fiber reinforced roller compacted concrete at different curing temperatures.