| 偏高岭土对高流动性钢纤维混凝土早期力学性能和细观结构的影响 |
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| 引用本文： | 于子豪,张彤炜,崔科旺. 偏高岭土对高流动性钢纤维混凝土早期力学性能和细观结构的影响[J]. 硅酸盐通报, 2021, 40(9): 2911-2920 |
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| 作者姓名： | 于子豪 张彤炜 崔科旺 |
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| 作者单位： | 兰州大学西部灾害与环境力学教育部重点实验室,兰州 730000;兰州大学土木工程与力学学院,兰州 730000 |
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| 基金项目： | 国家重点研发计划(2018YFC1504700,2019YFC1806004);中国博士后科学基金面上项目(2019M653791);甘肃省自然科学基金面上项目(20JR5RA259);中央高校基本科研业务费专项资金自由探索项目(lzujbky-2020-pd08) |
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| 摘 要： | 为了提高泵送混凝土流动性及早期力学性能,降低水泥用量,本文研究了高流动性偏高岭土和钢纤维复合混凝土的流动性、抗压和抗拉强度、弹性模量、破坏形态和微观结构,并在此基础上评价了偏高岭土和钢纤维对混凝土性能的影响.结果表明,随着钢纤维和偏高岭土含量的增加,浆体的流动性降低,偏高岭土影响更加显著.偏高岭土提高了钢纤维混凝土养护...
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| 关 键 词： | 偏高岭土 钢纤维 高流动性混凝土 力学性能 微观机制 |
| 收稿时间： | 2021-03-26 |
Effect of Metakaolin on Early Mechanical Property and Microstructure of High Fluidity Steel Fiber Reinforced Concrete |
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| YU Zihao,ZHANG Tongwei,CUI Kewang. Effect of Metakaolin on Early Mechanical Property and Microstructure of High Fluidity Steel Fiber Reinforced Concrete[J]. Bulletin of the Chinese Ceramic Society, 2021, 40(9): 2911-2920 |
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| Authors: | YU Zihao ZHANG Tongwei CUI Kewang |
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| Affiliation: | 1. Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou 730000, China;2. College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China |
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| Abstract: | To improve the workability of the pumped concretes at early curing stage, which are normally used in driven cast-in-place piles, this paper investigated thefluidity, compressive and tensile strength, elastic modulus, destruction morphology and microstructure of high fluidity metakaolin (MK) and steel fiber (SF) concrete. Then, the effects of metakaolin and steel fiber on concrete properties were evaluated. The results show that the fluidity of the paste decreases with the increase of steel fiber or metakaolin respectively. As metakaolin contents increased, the increment of metakaolin dominates the fluidity of concrete, and the effect of steel fiber is not evident. The compressive strength, tensile strength and elastic modulus after 7 d curing increase with SF or metakaolin respectively, and metakaolin is the key factor effecting the strength of high fluidity MK-SF concretes. Whist the residual tensile strength and crack development are significantly dominates by steel fiber. From the scanning electronic microscope (SEM) images and X-ray diffraction (XRD) spectrogram, more stable hydrated calcium silicate (CSH) gel, monosulfide calcium sulphoaluminate hydrate (AFm) and polysulfide calcium sulphoaluminate hydrate (AFt) are produced by metakaolin addition. These products reduce the porosity and defects, and strengthen the bonding in interfacial transition zone. The metakaolin and steel fiber increase the viscosity of paste and the shear resistance of interfaces, which is essentially to hinder the relative movement of each component. Then, they have a coupling effect on reducing the fluidity of concrete. The mechanisms of metakaolin and steel fiber influencing the mechanical behavior of concretes are different. Generally, the steel fiber effects the cracking stage and the metakaolin influences the non-cracking stage in strain-stress curves. |
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| Keywords: | metakaolin steel fiber high fluidity concrete mechanical property micromechanism |
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