• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.25-35
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• 2006

This paper investigates the mechanical characteristics of reinforced lightweight soil (RLS) using waste fishing net. RLS used in this experiment consists of dredged soil taken from construction site of Busan New Port, cement, air foam and waste fishing net. Several series of laboratory tests were performed to compare behavior characteristics between RLS and unreinforced lightweight soil, in which the reinforced effect by waste fishing net on RLS was evaluated. The experimental results of RLS indicated that the stress-strain relationship and the unconfined compressive strength are strongly influenced by the content of waste fishing net. Compressive strength of RLS Increased with the increase in curing time and generally increased by adding waste fishing net, but the amount of increase in compressive strength was not proportional to the content of waste fishing net. In this test, the maximum increase in compressive strength was obtained at 0.25% content of waste fishing net. On the other hand, water content of RLS rapidly decreased up to 7 days of curing time and converged to constant value.

• Journal of environmental and Sanitary engineering
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• v.18 no.4
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• pp.36-44
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• 2003

The cement-based system among S/S(Solidification/Stabilization) is widely used to treat hazardous wastes. In this study, tannery sludge was solidified to evaluate the stabilization effects of using admixtures in the cement-based S/S. Fly ash as substitute also used to increase the strength of the S/S of hazardous waste. The compressive strength measurement and leaching experiment of chromium metal of solidified mortar were carried out to compare and evaluate the physical and chemical characteristics of solidified hazardous waste sludge. From the result of this study, there was increased of compressive strength by using AEW-3(early-hardening AE water reducing agent), and leaching concentration of chromium became low enough to satisfy the regulatory criteria. The successful solidification for the organic contaminant and heavy metal in hazardous waste should enable to treat by cement-based system using early-hardening AE water reducing admixture and fly ash as substituted cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.21-26
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• 2002

This paper is intended to verify the efficiency of anti-freeze agent and insulating form by analyzing the temperature history and the property of strength-increase about the concrete that is placed in the insulating form and normal form, using new type anti-freeze agent in batcher plant According to the results about the temperature history, while the lowest temperature shows 3$^{\circ}C$ in case of normal concrete + euroform, 4$^{\circ}C$ in case of normal concrete + insulating form, it shows 6$^{\circ}C$ in anti-freeze agent + the insulating form, so the effect is most favorable. The compressive strength with mixing anti-freeze agent or not, shows high in order of standard curing, structure-managing and open air-placed specimen and the concrete mixing anti-freeze agent shows the highest compressive strength-increase.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.668-671
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• 2004

Recently, the concern for mechanical properties at early age concrete are increasing because of the importance of the thermal stress and the determination of removal time of form work and prestressing work. In this study, an estimation for the development of compressive strength and elastic modulus with age in concretes isothermally cured $(10^{\circ}C,\;20^{\circ}C)$ and having W/C ratio of 30, 40, and $50\%$ were investigated. According to experiment results, the development of compressive strength and elastic modulus shows higher values at early ages as the W/C ratio decreases and curing temperature increases. When the maturity concept, for estimation of the strength, is adopted, a modification for W/C ratio is required at early ages.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.244-245
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• 2014

This is an experimental study on manufacturing of non-cement matrix. Materials like cement and blowing agent in foamed concrete is replaced by by-products from blast furnace slag and paper ash. Further, the experiment was performed by replacing alkali with red mud by (0, 5, 10, 15, 25, 35, 45) of weight of alkali (wt.%) in order to reduce the amount of expensive alkali acclerator. Sample Plain with density showed lowest. The compressive strength test result, showed a similar trend with density. And it showed that compressive strength of the RM-0.05 was highest.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.485-488
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• 2005

The results of an experiment on the sea water purification of the porous concrete using granular artificial zoelite and its influence on the physical and mechanical properties are reported in this paper. Two different sizes of coarse aggregate of 5$\∼$13, 13$\∼$20mm, and three of void ratio(15, 20 and 30 percent) for a given size of aggregate were used. In the water permeability, an aggregate of the size of 13$\∼$20mm is much higher than that of the 13$\∼$20mm, but the water permeability is smaller in the less design void ratio. and In the compressive strength, an aggregate of the size of 5$\∼$13mm is much higher strength than that of the 13$\∼$20mm, but the compressive strength is higher in the less design void ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.190-191
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• 2013

In this research, the fundamental experiment for colour concrete(by using pigment) has been invested. Fundamental properties and dyeability for the colour mortar as the changing replacement ratio of pigment has been tested. For the conclusion, with the increasing ratio of pigment, the flow and compressive strength for the mortar has been decreased, For the dyeability, there's little difference when replacement ratio of dyestuff changed when the colour is red and yellow, but large difference when the blue pigment was used. Consider about the workability and strength of the mortar, the optimum pigment's replacement ratio is fixed as 2.5%.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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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.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.959-964
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• 2002

The purpose of this study is to establish flexural behavior of high-strength concrete by means of both theoretical approach and experimental analysis of beams in which confinement stirrups have been introduced into pure bending zone. The experiment was carried out on full-scale high-strength reinforced concrete beams whose compressive strengths are 400 and 700kgf/cm$^2$, and confined with rectangular closed stirrups. The test results are reviewed in terms of flexural capacity and ductility.

• Fire Science and Engineering
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• v.25 no.1
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• pp.42-49
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• 2011

In the high temperature situation like in a fire, the high strength of concrete (HSC) has extreme danger named explosive spalling. It is assumed that the major cause of explosive spalling is water vapour pressure inside concrete. This paper examines the effect of the compressive strength and the moisture content on the initial occurrence of explosive spalling. For the effective experiment of the initial explosive spalling, the curve of ISO834 temperature profile is applied on the basis of 15 minute and 30 minute. As a result, the more increase the compressive strength and the moisture content, the more increase the occurrence and phenomenon of explosive spalling. This paper analyzes the territory of explosive spalling depending the compressive strength and the moisture content. The explosive spalling is not examined in the case of the compressive strength 50~100 MPa and the moisture content below 3% and the compressive strength over 100 MPa and the moisture content below 1%. Also, due to the HSC, which makes it more difficult to transport vapour and moisture, very high vapour-pressure may occur close to the surface, there is a greater risk that HSC spalls compared with normal strength concrete (NSC).