• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.35-43
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• 2022

The aim of this work was to a comparative review the performance of high calcium silicate cement (HSCSC) and that of ordinary Portland cement(OPC) and blast furnace slag cement(S/C). The result of the compressive test confirmed that the compressive strength development rate of high calcium silicate cement concrete at the age of 3 days was 73.6% that of ordinary Portland cement concrete. However, at the age of 28 days, the strength development rate of high calcium silicate cement increased to about 107.0% compared to ordinary Portland cement. In addition, the test of the chloride ion penetration resistance of concrete showed that at the age of 28 days, the passed charge decreased by 73.4% and 93.0%, respectively, in blast furnace slag cement and high calcium silicate cement compared to ordinary Portland cement, and at the age of 56 days, it decreased by 79.1% and 98.3%, exhibiting excellent resistance to chloride ion penetration. In particular, it was confirmed that the rate of decrease in the passed charge with age was higher in high calcium silicate cement than in ordinary Portland cement and blast furnace slag cement.

• Journal of Urban Science
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• v.12 no.1
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• pp.1-10
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• 2023

The cement industry is a major source of carbon dioxide emissions. Reduction in emissions in this sector is an important issue. Calcium silicate cement is a type of alternative to ordinary Portland cements which contributes to the reduction in carbon dioxide emissions. However, because the type of cement is a non-hydraulic material, there are limitations to its application in the field. The effects of pre-curing periods on the physical characteristics of ordinary Portland cement pastes with calcium silicate cement in the present study were investigated. The Independent variable is the pre-curing period. The pre-curing period varied from 0 to 5 hrs, considering the hydration characteristics of ordinary Portland cement. The carbonation curing of the ordinary Portland cement pastes with the calcium silicate cement after pre-curing was conducted. The concentration of gaseous CO₂ was fixed at 20 %. The test results showed that the pre-curing period led to the pore structural change of the pastes, which in turn could affect the further reaction under the long-term curing condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.93-94
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• 2023

This study evaluated the mechanical properties and microstructure of calcium silicate cement based paste according to carbonation curing conditions. As a result, both compressive strength and carbonation depth increased with the carbonation curing period.

• Cement Symposium
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• no.27
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• pp.6-13
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• 2000

• Resources Recycling
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• v.32 no.6
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• pp.10-17
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• 2023

Calcium silicate cement (CSC) is an environmentally sustainable, low-carbon cement and has garnered significant attention in recent studies. However, the pre-curing step required to activate the carbon dioxide reaction and to handle the sample. This study aimed to examine the viability of extending the application of CSC without pre-curing by enhancing initial strength by mixing calcium sulfoaluminate (CSA) fast-hardening cement into CSC. The investigation assessed changes in compression strength and Q-XRD mineral characteristics concerning variations in the mixing ratio of CSC and CSA fast-hardening cement within a carbon dioxide atmosphere. The compressive strength results indicated that the 3-day and 7-day strengths were 14.18 MPa and 22.98 MPa, respectively, under the 50% CSC condition, meeting the type 1 cement KS standard. Mineral characteristics analysis revealed an increase in calcite mineral, a byproduct of the carbon dioxide reaction, contributing to strength enhancement. Even after seven days, substantial quantities of unreacted rankinitene and pseudowollastonite were observed, as well as dicalcium silicate and yeelimite, which are hydrated minerals. This observation was confirmed the possibility of strength improvement after 7 days.

• International Journal of Concrete Structures and Materials
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• v.4 no.1
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• pp.37-43
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• 2010

Theoretical models based on modern interpretations of the morphology and interactions of cement hydration products are developed for prediction of the mechanical properties of hydrated cement paste (hcp). The models are based on the emerging nanostructural vision of calcium silicate hydrate (C-S-H) morphology, and account for the intermolecular interactions between nano-scale calcium C-S-H particles. The models also incorporate the effects of capillary porosity and microcracking within hydrated cement paste. The intrinsic modulus of elasticity and tensile strength of hydrated cement paste are determined based on intermolecular interactions between C-S-H nano-particles. Modeling of fracture toughness indicates that frictional pull-out of the micro-scale calcium hydroxide (CH) platelets makes major contributions to the fracture energy of hcp. A tensile strength model was developed for hcp based on the linear elastic fracture mechanics theories. The predicted theoretical models are in reasonable agreements with empirical models developed based on the experimental performance of hcp.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.79-80
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• 2023

After the Second Industrial Revolution, as global warming caused by environmental issues has intensified, the CO₂ emissions from the cement industry have become an urgent challenge. Therefore, this study aimed to reduce and utilize CO₂ emissions by using CO₂-reducing Calcium Silicate Cement.

• Cement Symposium
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• no.2
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• pp.38-50
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• 1975

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.47-48
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• 2023

In the domestic industrial sector, greenhouse gases emitted from the cement industry account for about 10%, with most of them generated during the cement clinker calcination process. During the calcination process, 57% of carbon dioxide is emitted from the decarbonation reaction of limestone, 30% from fuel consumption, and 13% from electricity usage. In response to these issues, the cement industry is making efforts to reduce carbon dioxide emissions by developing technologies for raw material substitution and conversion, improving process efficiency by utilizing low-carbon alternative heat sources, developing CO₂ capture and utilization technologies, and recycling waste materials. In addition, due to the limitations in purchasing and storing industrial byproducts generated from industrial facilities, many studies are underway regarding the recycling of construction waste. Therefore, this study analyzes the manufacture of calcium silicate cement (CSC), which can store carbon dioxide as carbonate minerals in industrial facilities, and aims to contribute to the development of environmentally friendly regenerated cement using construction waste.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.141-142
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• 2023

In this study, the strength development characteristics of calcium silicate cement mixed mortar according to carbonation hardening conditions were evaluated. As a result of measuring the compressive strength, the strength increased according to the carbonation hardening time, and the strength increase rate was higher for the specimen with a CO₂ concentration of 20%.