Relationship between CaO hydration activity and its expansive characteristics in C4A3$-CaSO4-CaO systems

HAN Jianguo; YAN Peiyu; ZHANG Youhai

doi:10.16511/j.cnki.qhdxxb.2018.26.003

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Journal of Tsinghua University(Science and Technology) ›› 2018, Vol. 58 ›› Issue (2) : 217-224. DOI: 10.16511/j.cnki.qhdxxb.2018.26.003

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Relationship between CaO hydration activity and its expansive characteristics in C₄A₃$-CaSO₄-CaO systems

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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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expansive agent / mineral composition / hydration activity / water-loss-expansion / in-situ reaction

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HAN Jianguo, YAN Peiyu, ZHANG Youhai. Relationship between CaO hydration activity and its expansive characteristics in C₄A₃$-CaSO₄-CaO systems[J]. Journal of Tsinghua University(Science and Technology). 2018, 58(2): 217-224 https://doi.org/10.16511/j.cnki.qhdxxb.2018.26.003

References

[1] 韩建国, 阎培渝, 侯维红. C4A3$-CaSO4-CaO体系在硅酸盐水泥浆体中的膨胀能力[J]. 硅酸盐学报, 2016, 44(8):1120-1125. HAN J G, YAN P Y, HOU W H. Expansion character of C4A3$-CaSO4-CaO system in Portland cement paste[J]. Journal of the Chinese Ceramic Society, 2016, 44(8):1120-1125. (in Chinese)[2] MEHTA P K, MONTEIRO P J M. Concrete:microstructure, properties, and materials[M]. 4th ed. New York:McGraw-Hill Press, 2014.[3] RIBEIRO M S S. Expansive cement blend for use in shrinkage-compensating mortars[J]. Materials and Structures, 1998, 31(6):400-404.[4] KLEIN A, KARBY T, POLIVKA M. Properties of an expansive cement for chemical prestressing[J]. ACI Special Journal, 1961, 58(7):59-62.[5] KOKUBU M. Use of expansive components for concrete in Japan[J]. ACI Special Publication, 1973, 38:353-378.[6] BISSONNETTE B, JOLIN M, GAGNÉ R, et al. Evaluation of the robustness of shrinkage-compensating concrete repair concretes prepared with expansive components[J]. ACI Special Journal, 2016, 307:1-18.[7] MO L W, DENG M, TANG M S. Effects of calcination condition on expansion property of MgO-type expansive agent used in cement-based materials[J]. Cement and Concrete Research, 2010, 40(3):437-446.[8] AYLWARD T J. Studies of volume change in expansive cements[M]. West Lafayette:Purdue University, 1965.[9] KLEIN A, TROXELL G E. Studies of calcium sulfoaluminate admixtures for expansive cements[C]//ASTM Proceeding, West Conshohocken, 1958:968-1008.[10] OGAWA K, ROY D M. C4A3$ hydration ettringite formation, and its expansion mechanism:I. Expansion; Ettringite stability[J]. Cement and Concrete Research, 1981, 11(5-6):741-750.[11] OGAWA K, ROY D M. C4A3$ hydration, ettringite formation, and its expansion mechanism:Ⅱ. Microstructural observation of expansion[J]. Cement and Concrete Research, 1982, 12(1):101-109.[12] 韩建国, 阎培渝, 侯维红. C4A3$-CaSO4-CaO体系在硅酸盐水泥浆体中的膨胀机理[J]. 硅酸盐学报, 2016, 44(11):1543-1551. HAN J G, YAN P Y, HOU W H. Expansion mechanism of C4A3$-CaSO4-CaO in Portland cement paste[J]. Journal of the Chinese Ceramic Society, 2016, 44(11):1543-1551. (in Chinese)[13] SERRIS E, FAVERGEON L, PIJOLAT M, et al. Study of the hydration of CaO powder by gas-solid reaction[J]. Cement and Concrete Research, 2011, 41(10):1078-1084.[14] RAMACHANDRAN V S, SEREDA P J, FELDMAN R F. Mechanism of hydration of calcium oxide[J]. Nature, 1964, 201(4916):288-289.