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Relationship between CaO hydration activity and its expansive characteristics in C4A3$-CaSO4-CaO systems |
| HAN Jianguo1, YAN Peiyu1, ZHANG Youhai2 |
1. Department of Civil Engineering, Tsinghua University, Beijing 100084, China;
2. Denka Infrastructure Technologies Co., Ltd., Shanghai 200336, China |
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Abstract The effects of two C4A3$-CaSO4-CaO (CCC) systems were evaluated to explain the cause of water-loss-expansion of CCC systems introduced into concrete. This study measures the influences of two CCC systems on the concrete workability, compressive strength, autogenous shrinkage, dry shrinkage, hydration heat and XRD pattern. The results show that the CCC system can significantly compensate for concrete autogenous shrinkage and drying shrinkage, and that the CaO component of the CCC system is responsible for the water-loss-expansion behavior during drying. The dead burn during manufacturing or hindered hydration in low water-to-binder concrete allowed the CaO to continue to hydrate for unsaturated conditions while resulted in in-situ hydration and expansion. The results show the relationship between the CCC component activity and the expansive characteristics. Thus, CaO dead burn should be avoided and the CCC concentration should be reduced in low water-to-binder concrete.
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| Keywords
expansive agent
mineral composition
hydration activity
water-loss-expansion
in-situ reaction
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Issue Date: 15 February 2018
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2018,
Vol. 58
