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| Effect of metakaolin content on performance of high strength manufactured sand concrete |
| LI Bo1, ZHOU Hailong1,2*, LIANG Yujing2, HE Yong3, LYU Zhigang3, YANG Fuguang3 |
| 1. Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China; 2. College of Material Science and Art Design, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China; 3. Inner Mongolia Road and Bridge Group Co. Ltd., Hohhot, Inner Mongolia 010051, China |
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Abstract The effects of metakaolin(MK)content on the compressive strength and resistance to chloride ion penetration of high strength manufactured sand concrete were studied by using scanning electron microscope(SEM), mercury intrusion method(MIP), and rapid chloride ion mobility coefficient(RCM)methods. The study finds that the addition of MK can effectively improve the mechanical pro-perties and resistance to chloride ion penetration of high strength manufactured sand concrete. With the increase of the amount of MK, both the compressive strength and the resistance to chloride ion pene-tration increase first and then decrease. The optimal MK content is 8%. At this time, the 28-day compressive strength is 98.5 MPa, which is increased by 13% compared with the benchmark group, and the chloride ion migration coefficient is 1.89×10-12 m2/s, which is 60% lower than the benchmark group. The microstructure test shows that the appropriate amount of metakaolin can effectively promote cement hydration. The synergistic effect of MK particle nucleation effect and micro aggregate filling effect of metakaolin particles makes the microstructure of the machined sand concrete more uniform and dense. The number of harmful holes and harmful holes of manufactured sand concrete are reduced, and fewer harmful holes are increased, and thereby improving the compressive strength and resistance to chloride ion penetration of the sand concrete.
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Received: 11 March 2020
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