• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.13-16
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• 2003

There is no study that application of the maturity using H.B.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.13.1-16
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• 2003

There is no study that application of the maturity using H.S.C and H.S.C. Also activation energy has different values according to the cement, admixture and water-cement ratio. Therefore to make accurate explanation for the effect of temperature on concrete strength development properties, it is necessary that activation energy value according to the kind of cement is reviewed. This study compares and estimates equivalent age using activation energy value obtained by this experiment and Freiesleben activation energy value with compressive strength of concrete. As the result of this study, activation energy value obtained by this study has more accurate explanation of temperature's influence on concrete strength development than Freiesleben activation energy value.

• 시멘트 심포지엄
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• 1호
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• pp.31-40
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• 1973

Cement industry in Korea, has made a remarkable progress in recent years and now annual production capacity is about 9,000,000 tons. However, this large amount of cement is only one kind of general portland cement type I, and it is urgent problem for ceme

• 한국건축시공학회지
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• 제8권2호
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• pp.99-106
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• 2008

To improve concrete tensile strength and bending strength, New plan that have more economical and simple manufacture process is groped. By an alternative plan, chemical pre-stressed concrete is presented. In this study, we analyzed the rheological properties of cement paste with the kind and replacement ratio of k-type CSA type expansive additives that is used mainly in domestic. and we suggested that the algorithm of a mixing plan in the chemical pre-stressed concrete and from this, we presented the basic report for the right mixing plan. From the results, Flow increased more or less according to use of expansive additives. This phenomenon was observed by increasing paste amount that shows as substitution for expansive additives that specific gravity is smaller than that of cement. As linear regression a result supposing paste that mix expansive additives by Bingham plastic fluid. The shear rate and shear stress expressed high interrelationship. therefore, flow analysis of quantitative was available. The plastic viscosity following to replacement ratio of expansive additives is no change almost, the yield value is decreased in proportion to the added amount of expansive additives. Through this experiment, we could evaluate rheological properties of cement paste using the expansive additives. Hereafter by an additional experiment, we must confirm stability assessment of material separation by using the aggregate with the kind and replacement ratio of expansive additives.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.124-129
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• 1995

In this study proposed to rapid and simple methid of test for early evaluation of strength of cement. The obtained results through a series of experiment are summarized as follow. The resistance ratio was decreased as the increase of water-cement ratio. The compressive strength of cement was increased as the resistance ratio increase. The experimental results of compressive strength of cement is shown in the same value no relation with the kind of cement respectively.

• 한국구조물진단유지관리공학회 논문집
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• 제5권2호
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• pp.191-197
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• 2001

In this study, the admixtures for agents for enduring cold weather used widely are collected and applied to cement mortar to analyze the strength development due to variation of curing temperature at early age. The test results show that anti-freezing admixture have some problems due to high chloride content, which may cause the corrosion of reinforcement embedded in concrete. However, the mortar applied by accelerator and another kind of agent for enduring cold weather produced by S company lead to delay of strength development in low temperature. Also, it is clarified that there are no significant problems for cement mortar in strength development due to low temperature if a suitable kind of agent enduring cold weather is used and cement mortar is cured for more than $7.5^{\circ}D.D$ at early age.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.183-186
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• 1998

This paper deals with 28, 56, 91 days age compressive strength and ratio of weight when OPC and Low-Heat cement mortar immersed in chemical solution. As a result of experiment, the resistance of Low-Heat Cement motar in chemical attack is more effective than that of OPC, because of lower $C_3$A content and Pozzolanic reactions. Especially in long term age compressive strength, Low-Heat cement mortar shows higher strength in all kind of chemical solution compared with compressive strength of OPC motar.

• Advances in Computational Design
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• 제1권1호
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• pp.27-35
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• 2016

The influences of chloride-free components of the cement additive: triethanolamine, triisopropanolamine, sodium hyposulfite and calcium gluconate on the 1d, 3d and 28d compressive strength of cement were investigated by response surface methodology. It found the early strength activators, triethanolamine and sodium hyposulfite could enhance the 1d strength of cement effectively but they did not contribute to the 3d strength enhancement, and further their interaction was able to decrease the 28d strength of cement. Calcium gluconate was not that effective for the strength enhancement on 3 and 28 days when it's simply dosed. However the interaction effect of calcium gluconate with triisopropanolamine could strongly favor the strength enhancement of cement after 3 days. Results indicated it was necessary to focus attention on the potential interactions among the chemical components. And for the concern of four chemicals studied in this paper, it was feasible to formulated a kind of chloride-free cement additive that can be effective for the early strength of cement and its the strength after 3 days.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.445-452
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• 2001

Generally, OPC(ordinary portland cement) is used for grouting in Korea, and bentonite has usually been added to prevent the deposition of cement particles. The dispersion of CB(cement bentonite) grout is influenced by variable factors i.e. water to cement ratio, particle size of cement, kind of bentonite, adding volume, methods of adding, viscosity of CB grout materials and curdling time. Among variable factors, the viscosity of CB grout materials is influenced by the dispersion, and dispersion is improved as increasing the mixing speed. In this paper, described a suitable mixing speed of the High Speed Mixer in field, engineering characteristics of CB grout materials vary with the water to cement ratio and the mixing speed as well as confirming the state of dispersion.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.14-18
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• 1995

Since cement is one of materials of concrete and have an important effect upon physical properties of concrete, the quality characteristics of ordinary portland cement in domestic market are evaluated in this study. For this purpose, eight kinds of cement are selected and tested on the specific gravity, normal consistency, setting time, fincness, and compressive strength of cement ranged from 300kg/$\textrm{m}^3$ to 600kg/$\textrm{m}^3$ are tested for each kind of cement. As a result,ordinary portland cement in domestic market are satisfied with physical performance prescribed by KS L 5201(Portland Cement) and when unit weight of cement is 300~600kg/$\textrm{m}^3$, the maximum compressive strength of concrete cylinder is showed to be about 440-540kgf/$\textrm{cm}^2$.