Experimental research on the microstructure and compressive and tensile properties of nano-SiO2 concrete containing basalt fibers
Experimental research on the microstructure and compressive and tensile properties of nano-SiO2 concrete containing basalt fibers
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DOI：
10.1016/j.undsp.2017.07.001
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发表时间：
2017-09
影响因子：
6.4
通讯作者：
Q. Ma;Ying Zhu
中科院分区：
文献类型：
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作者：
Q. Ma;Ying Zhu
城市地下空间资源是城市可持续发展的重要资源。传统的混凝土已不能满足地下工程的需要。采用不同掺量的纳米SiO2和玄武岩纤维配制高性能混凝土，测定其抗压和抗拉强度。通过对混凝土微观结构的分析，探讨了纳米SiO2和玄武岩纤维对混凝土强度的影响机理。所生产的混凝土中水泥水化产物随纳米SiO2掺量的不同而变化。当纳米SiO2用量在0 ~ 1.8%之间时，C-S-H凝胶和AFt晶体的质量随着纳米SiO2用量的增加而逐渐增加。当纳米SiO2掺量为1.2%时，C-S-H凝胶和AFt晶体存在最佳掺量，混凝土的密实性较好，与抗压强度试验结果相一致。当玄武岩纤维掺量为3 ~ 4 kg/m3时，玄武岩纤维与水泥基体结合紧密，混凝土劈拉强度显著提高。当玄武岩纤维掺量超过5 kg/m3时，玄武岩纤维聚集在一起，导致玄武岩纤维与水泥基体之间的结合较弱，容易从水泥基体中剥离。当纳米SiO2和玄武岩纤维掺量分别为1.2%和3 kg/m3时，混凝土微观结构致密，强度提高最大，抗压强度和劈裂抗拉强度分别比素混凝土提高9.04%和17.42%。对玄武岩纤维纳米SiO2混凝土力学性能的宏观测试结果与微观结构分析结果吻合较好。
Urban underground space resources are gaining increasing attention for the sustainable development of cities. Traditional concrete cannot meet the needs of underground construction. High-performance concrete was prepared using varying dosages of nano-SiO2and basalt fiber, and its compressive and tensile strength was measured. The concrete microstructure was analyzed and used to assess the mechanisms through which the nano-SiO2and basalt fibers affect the strength of concrete. The cement hydration productions in concrete produced varied with the dosage of nano-SiO2. When the nano-SiO2dosage was between 0 and 1.8%, the mass of the C-S-H gel and AFt crystals increased gradually with the nano-SiO2dosage. When the nano-SiO2dosage was 1.2%, optimum amounts of C-S-H gel and AFt crystals existed, and the compactness of concrete was well, which agreed with the results of the compressive strength tests. When the basalt-fiber dosage was between 3 and 4 kg/m3, the basalt fibers and the cement matrix were closely bonded, and the splitting tensile strength of the concrete markedly improved. When the basalt-fiber dosage exceeded 5 kg/m3, the basalt fibers clustered together, resulting in weak bonding between the basalt fibers and the cement matrix, consequently, the basalt fibers were easily pulled apart from the cement. When the nano-SiO2and basalt fiber dosages were 1.2% and 3 kg/m3, respectively, the compactness of the concrete microstructure was well and the strength enhancement was the greatest; additionally, the compressive strength and splitting tensile strength were 9.04% and 17.42%, respectively, greater than those of plain concrete. The macroscopic tests on the mechanical properties of the nano-SiO2concrete containing basalt fibers agreed well with the results of microstructure analysis.