• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.4
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• pp.1-9
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• 2020

This study conducted to understand effects of CA (CaAl₂O₄) and CA₂ (CaAl₄O₇) ratio on chloride binding ability and compressive strength and pore structure of cement mortar incorporating mixture of CA and CA₂. The Portland cement based specimens were mixed with the clinkers CA and CA₂, and these calcium aluminate clinker mixture were replaced 0, 5, 10% by weight of cement. After all the test specimens were cured for 28 days under water curing, they were immersed in the distilled water and NaCl solution. As a result, 28 days compressive strength of all specimens was similar, and As the replacement ratio of calcium aluminate clinker in the specimen increased, Friedel's salt production tended to increase. However, it was dependent on the amount of Al₂O₃ in the level of 5% replacement and CA ratio in the level of 10% replacement. Through equilibrium isotherm result, it was also indicated that as replacement ratio of calcium aluminate clinker in cement matrix increased, chloride binding capacity was improved, and chloride penetration was suppressed. In this study, the specimen replaced with 10% of the calcium aluminate clinker mixture (CA 39%, CA₂ 60%) was remarkable to control chloride attack. We figured out necessity to understand optimal CA/CA₂ ratio to effectively apply CA₂ as a sustainable building material by improving the chloride binding ability in Portland cement based system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.238-239
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• 2018

This paper presents the synthesis results of CaO-Al₂O₃ system clinker using the CaCO₃ and the Al₂O₃ according to the synthesis methods dependent on the temperature. The purpose of this study is the formation of the CaO-Al₂O₃ system clinker containing high ratio of CaO·2Al₂O₃ (CA₂). The maximum sintering temperature for the synthesis of CaO-Al₂O₃ compounds was 1250℃, 1300℃ and 1400℃. The CaO-Al₂O₃ compounds was sintered at the maximum sintering temperature for three hours. After sintering, the compounds was analyzed using X-ray diffraction method. The 12CaO·7Al₂O₃ (C1₂A₇) and CaO·Al₂O₃ (CA) increased as elevating the maximum sintering temperature whereas the CA₂ decreased. Especially, at the 1250℃ of maximum sintering temperature, the un-reacted CaO and Al₂O₃ was identified.