玄武岩纤维增强粉煤灰水泥浆体的耐久性及缺陷分析

Long-Term Performances and Defects of Basalt Fiber Reinforced Cement Paste with Fly Ash

采用环境扫描电镜和能谱仪表征了玄武岩纤维的耐酸碱腐蚀性能。通过玄武岩纤维的抗弯增强效果和相对动弹性模量的变化情况评定了玄武岩纤维在水泥基体中的耐久性。用XCT(X-ray computed tomography)研究了玄武岩纤维对掺或不掺粉煤灰的水泥浆体内部缺陷的尺寸与分布的影响。结果表明:玄武岩纤维的耐酸腐蚀性能优于耐碱腐蚀性能;粉煤灰的掺入能显著提高玄武岩纤维增强水泥的后期抗折强度提高率和相对动弹性模量增长速率;粉煤灰和玄武岩纤维的掺入均使基体内部总的缺陷体积分数增大,但粉煤灰掺入玄武岩纤维水泥浆体明显降低了尺寸在0.007～0.01mm3内的缺陷数量。

The environmental resistance of basalt fiber was characterized by environmental scanning electron microscope and energy dispersive spectrometer, respectively. The flexural reinforcement of basalt fiber and relative dynamic modulus of elasticity were in- vestigated to evaluate the durability of basalt fiber, The effect of basalt fiber on the defects size and distribution of cement with or without fly ash was investigated by the X-ray computed tomography （XCT）. The results indicate that the acid resistance of the basalt fiber is better than the alkali resistance. The flexural reinforcement of basalt fiber and relative dynamic modulus of elasticity of basalt fiber reinforced cement at late age are significantly increased after fly ash is added. The defect volume fraction of cement paste increases with the addition of fly ash and basalt fiber. The defect number of basalt fiber reinforced in the range of 0,007-0.01 mm3 is decreased due to the addition of fly ash,