不同配合比下玄武岩纤维水泥砂浆的流动度及力学性能

Fluidity and Mechanical Properties of Basalt Fiber Reinforced Cement Mortar at Different Mixing Ratios

摘要:

为研究玄武岩纤维增强水泥砂浆（Basalt Fiber Reinforced Cement Mortar，BFRCM）在不同配合比下的流动度和力学性能，通过改变水灰比、长短纤维混掺比例及添加减水剂来改变配合比，设计了2种纤维长径比、7种玄武岩纤维体积分数、3种水灰比、3种减水剂质量分数共制备了14组BFRCM试样。研究了不同配合比下BFRCM的流动度、抗压强度及抗折强度，通过峰值荷载后BFRCM的荷载-位移曲线的归一化处理量化分析了试样断裂后BFRCM的断裂韧性。结果表明，BFRCM的流动度随着玄武岩纤维体积分数的增加、水灰比的降低、减水剂的减少以及短纤维占比的增加而降低。水灰比的增加对BFRCM的抗压强度影响较小，且会降低其抗折强度。减水剂的应用对BFRCM的抗压、抗折强度存在一定的负面影响。长短玄武岩纤维的混掺能够通过其协同效应有效提升BFRCM的抗压和抗折强度，然而过多的短纤维占比会减弱玄武岩纤维对BFRCM的增强效果。增加玄武岩纤维体积分数、 提高水灰比均能在一定范围内提升BFRCM峰值荷载后的断裂韧性。然而，长短纤维混掺中短纤维占比的增加和减水剂的应用则对BFRCM峰值荷载后的断裂韧性产生负面影响。

关键词:玄武岩纤维增强水泥砂浆;流动度;力学性能;纤维协同增强效应

Abstract:

To investigate the fluidity and mechanical properties of basalt fiber reinforced cement mortar （BFRCM） at different mixing ratios， the mixing ratio of BFRCM was adjusted by changing the water-cement ratio， the contents of water reducers， and the mixing ratios of long and short fibers. Fourteen groups of BFRCM samples were prepared by using 2 kinds of fiber aspect ratios， 7 kinds of basalt fiber volume dosages， 3 kinds of water-cement ratios， and 3 dosages of water-reducing agents. The fluidity， compressive strength， and flexural strength of the BFRCM at different mix ratios were analyzed， the load-displacement curve of the BFRCM after peak load was normalized， and the fracture toughness of the BFRCM after specimen fracture was quantitatively analyzed. The results show that the fluidity of the BFRCM decreases with increasing basalt fiber content， decreasing water-cement ratio， decreasing water reducer， and increasing short fiber proportion. The increase in the water-cement ratio has little effect on the compressive strength of the BFRCM but reduces its flexural strength. The application of the water-reducing agent has a certain negative impact on the compressive and flexural strength of the BFRCM. The blending of long and short basalt fibers can effectively improve the compressive and flexural strength of the BFRCM through its synergistic effect， but too much short fibers can weaken the strengthening effect of basalt fibers on the BFRCM. Increasing the content of basalt fiber and the water-cement ratio can improve the fracture toughness of the BFRCM after peak load within a certain range. However， the increase in short fiber ratios and the application of water-reducing agents negatively affect the fracture toughness of the BFRCM after peak load.

Key words:basalt fiber reinforced cement mortar (BFRCM);fluidity;mechanical properties;fiber synergistic effect