• Computers and Concrete
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• 제31권2호
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• pp.97-110
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• 2023

This study investigates experimentally the impact of magnetized water (MW) on the fresh and hardened characteristics of concrete. Five types of MW are produced using magnetic fields of 1.4 and 1.6 Tesla for treating water with 100, 150, and 250 cycles. The concrete properties are assessed using the slump test, compressive strength test, scanning electron microscopy (SEM) analysis, energy dispersive X-ray analysis (EDX), and Fourier transform infrared spectrophotometry (FTIR). Furthermore, the chemical-physical characteristics of tap water (TW) and MW are evaluated. The results showed the magnetic field intensity has a significant impact on the magnetization effect; the best magnetizing conditions were found when TW was exposed successively to magnetic fields of 1.6 T and 1.4 T for 150 cycles. In addition, 150 MW cycles can be used to improve the compressive strength and workability of concrete by 40% and 17%, respectively. pH, total dissolved solids, and electrical conductivity improved by 15%, 17%, and 7%, respectively, when using MW. Additionally, MW can be used to enhance cement hydration chemical processes and made concrete's structure denser.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.133-136
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• 1994

This study is to investigate properties of the ultra high-strength concrete using silica rume and fly ash. For this purpose, the properties of fresh concrete and hardened concrete are examined with varing water-cement ratio, silica fume and fly ash content and so on. From these test results, it is possible to maunfacture the miximum strength of 1, 200kg/$\textrm{cm}^2$ with cement content 800kg/$\textrm{m}^3$, 18% water-cement ratio, 105 silica fume content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.30-35
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• 1995

This paper presents fundamental experiment for the properties of high performance concrete in its fresh and hardened state made with ground granulated blast-furnace (GGBF) slag. The result is that the effect of decreasing xoncrete temperature is to the mixing ratio of GGBF slag, but it presents disadvantage in the slump loss phase. In addition to, we know that the splitting tensile strength, compressive strength and elastic modulus of concrete mixed with high fineness GGBF slag are increased at age 28days.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.422-429
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• 1997

In recent years, concrete construction have become larger and higher and are demanding high performance concrete with lower heat to prevent thermal cracking, far greater workability, high strength and durability. Application of low heat portland(Type IV) cement for the high performance concrete is the best solution to satisfied those requirements. Here are explained the basic properties of fresh concrete as well as hardened concrete of high performance concrete using low that portland cement.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.79-82
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• 2003

In this study, non-sintering cement is produced by only blending granulate blast furnace slag with phosphogypsum as main materials, and small amounts of hydrate lime or waste lime as activators. This paper was investigated physical properties of fresh concrete and hardened concrete using non-clinker cement according to various mixing ratio. Results obtained from this study have shown that concrete using non-clinker cement could be used for structural concrete and concrete 2th production as binder.

• 한국농공학회지
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• 제45권3호
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• pp.41-49
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• 2003

In this study, durability performance of blended cement mortars is evaluated when various mineral admixtures are used with the cement. A comprehensive evaluation of the effects of mineral admixtures on the mortar performance was made. The properties of fresh and hardened blended mortars investigated include slump flow and compressive strength. The durability characteristics of cement materials incorporating the mineral admixtures under various physical and chemical causes of deterioration was investigated. The laboratory test results indicate that mechanical and durability properties of blended cement mortars have superior performance rather than ordinary cement mortars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.825-828
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• 2006

In this paper, experimental studies are performed to find out properties of crack according to the change of curing conditions of flyash concrete. To study the effect of curing conditions on flyash concrete, slump, bleeding, air content and hydration temperature of fresh concrete are measured according to various curing conditions. In addition, the effect of caring conditions on compressive strength, tensile strength and Plastic drying shrinkage cracking of hardened concrete is also considered.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 봄 학술발표회 논문집
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• pp.12-15
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• 1993

Critical shortage of natural aggregate for production of concrete is developing in many urban area. At the same time increasing quantities of demolished concrete form deteriorated and obsolete structures are generated as a waste material in the same areas. The reuse of a waste concrete may settle the problems of environmental pollution and shortage of adquate aggregate, Therefore, this study is to reuse a waste concrete as aggregate for concrete, It is the purpose of this present study to investigate and analyze how the addition rates of superplasticizer and curing condition affect the properties of fresh and hardened recycled aggregate concrete comparing with those of ordinary concrete and crushed stone concrete.

• 한국세라믹학회지
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• 제25권5호
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• pp.532-540
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• 1988

Even the finest cement as having a specific surface area of 6.000~8.500$\textrm{cm}^2$/g (Blaine) is to convert into low-porosity hardened cement paste by the use of appropriate plasticizer. In this study, tests were carried out on such a special cement mix(fineness of 6.000$\textrm{cm}^2$/g, Ca-lignosulfonate plus k2CO3 as plasticizer and W/C=0.25) in comparison with ordinary Portland cement. Owing mainly to the high fineness of the cement powder and the low water-to-cement ratio, the hardened low-porosity cement paste showed a very tight microstructure, the pore texture of which consisted of micropores and wide pores only of small radii. The consequence of such mix was hence that the low-porosity special cement had excellent properties of early-high and very high strengths as compared to ordinary Portland cement. Its volume change when dried in the air or re-wetted, exhibited superor behaviour as well.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.163-168
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• 1994

If the concrete is exposed below freezing point of the outer temperature before hardened, the quality of the concrete will be lowered after hardened. Anti-freezing agent which doesn't corrode the steel bar and doesn't generate the alkali-aggregate reaction by noncholride recently developed in Japan and Northern Europe. But the effects of these agents are rarely known. Therefore, this study is desigend for analyzing the freezing properties at the condition of solution of solution and cement paste. And this study aims to present the reference data for practical use of the concrete works using anti-freezing agent.