• Cement Symposium
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• no.5
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• pp.88-93
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• 1977

시멘트 입도는 수화반응 속도에 밀접한 관계가 있으며 이로 인한 강도 발현 및 제반 물리특성에 크게 기여한다. 따라서 제품관리에 Blaine 및 sieve test로서 분말도를 check하고 있는바 이 분말도가 cement 물리특성에 미치는 영향을 실험실적으로 검토하였다.

• Cement Symposium
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• no.20
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• pp.22-25
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• 1992

• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.77-81
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• 1999

In order to investigate the effect of fineness on the properties of Portland cement, we prepared five kinds of portland cements with different Blaine values(2300, 2500, 3000, 3500, 45oo $\textrm{cm}^2$/g) and measured Ca(OH)2 analysis, hydration heat, the fluidity and the physical properties of them. According to the results, as the Blain value of cement is lower, the rate of hydration is delayed, and the hydration heat and the compressive strength are decreased. But the fluidity of cement paste is improved. Especially, the hydration heat of the cement with 2500$\textrm{cm}^2$/g of Blaine value is decreased about 15% compared with 3500 $\textrm{cm}^2$/g cement.

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.135-142
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• 2014

The heat of hydration can be reduced through the use of retarding agents. Typical retarding agents include sugar and glucose. However, these significantly delay the setting of cement paste. For the efficient use of sugar and glucose for mass concrete construction, it is necessary to develop a technique that can provide a setting behavior equivalent to that of plain concrete. In this work, the temperature rise of cement paste was monitored with the addition of various retarders including sugar and glucose. Hydrated cement powder was made with a water to cement ratio of 5 in order to accelerate the retarded cement pastes. It was found that the addition of hydrated cement powder in retarded pastes reduced the maximum temperature of cement paste. The use of hydrated cement powder could also successfully reduce the time to reach the maximum temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.545-548
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• 2008

In this study aluminium sulfate, Ca(OH)$_2$, K-R Slag and $Na_2SO_4$ were used as active admixtures and their concentration 1, 3, 5, 7 weight percent in cement. The physical properties of active admixtures cement mortar were investigated by flow test and compressive strength. It was found that the resulting active admixtures exhibited the higher compressive strength than OPC mortar up. From the test results, cement mortars added active admixture have a good fundamental property.

• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.115-125
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• 2015

This study investigated the fluidity, heat of hydration, setting time, strength development, and characteristics of hydration and pozzolanic reactions of high-strength high-volume ground granulated blast-furnace slag(GGBFS) blended cement pasts with the water-to-binder ratio of 20% by experiments, and analyzed the effects of the replacement ratio and fineness of GGBFS on the hydration and pozzolanic reaction. The results show that, in the high-strength mixtures with low water-to-binder ratio, the initial hydration is accelerated due to the "dilution effect" which means that the free water to react with cement increases by the replacement of cement by GGBFS, and thus, strengths at from 3 to 28 days were higher than those of plain mixtures with ordinary Portland cement only. Whereas it was found that the long term strength development is limited because the hydration reaction rates rapidly decreases with ages and the degree of pozzolanic reaction is lowered due to insufficient supply of calcium hydroxide according to large replacement of cement by GGBFS. Also, the GGBFS with higher fineness absorbs more free water, and thus it decreases the fluidity, the degree of hydration, and strength. These results are different with those of normal strength concrete, and therefore, should be verified for concrete mixtures. Also, to develop the high-strength concrete with high-volume of GGBFS, the future research to enhance the long-term strength development is needed.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.769-776
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• 2006

Recently, owing to the development of industry and the improvement of building techniques, concrete structures are becoming larger and higher. In hardening of these large connote structures, the heat of hydration gives rise to considerable thermal stress depending on the size and environmental condition of concrete, which might cause thermal cracking. Especially, the crack may cause severe damage to the safety and the durability of concrete structure. This study investigates the thermal properties of concrete according to several binder conditions, such as OPC, Belite rich cement(BRC), slag cement(SC), blast furnace slag(B) added cement fly ash(F) added cement and blast-furnace-slag and fly ash added cement. As a result of this study, the properly of concrete is most better BRC than others, and fly ash(25%) added cement and BFS(35%)-fly ash(15%) added cement gets superior effect in the control of heat hydration. But synthetically considered properties of concrete, workablity, strength heat hydration, etc, it is more effective to use mineral admixture. Especially, to be used Blast Furnace slag is more effective.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.86-93
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• 2020

Shotcrete concrete is generally used in the form of ready-mixed concrete products using type I ordinary portland cement(hereinafter referred to as OPC) and about 5% of accelerator mixed separately in the field. In this study, we tested the effect of addition of slag powder(SP) and limestone powder(LSP) on a penetration resistance, compressive strength of binder for shotcrete using calcium aluminate type accerlerator. And we analysed hydrates and pore structure effects on mortar performance. In the future, it is expected to be useful for manufacturing optimized composite cement as a binder for shotcrete.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.99-107
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• 2002

Impedance Spectroscopy (IS) has been used to study microstructure and hydration mechanism of cement pastes. In this work, the early hydration behaviour of portland cement paste with different blame values and contents of blast-furnace slag was investigated by IS. As slag was added to portland cement, the values of $R_{t(s+1)}$ (the solid-liquid phase resistance) and $R_{t(int)}$ were decreased in the early hydration period. It showed that hydration of cement paste containing slag was slower than it of the reference cement paste. As the content of slag was increased, the values of $R_{t(s+1)}$ was decreased. Furthermore, the diameter of semicircle, $R_{t(int)}$ observed at 72 hours was decreased with the increment of slag content. However, the values of $R_{t(s+1)}$ and $R_{t(int)}$ were increased with blame value of slag from the early hydration period.

• Cement Symposium
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• s.36
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• pp.88-95
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• 2009