• Journal of Industrial Technology
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• v.27 no.A
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• pp.103-110
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• 2007

Concrete is a material that will crack during its service life by its very nature. For bridge decks this is especially significant as these cracks allow accelerated ingress of chlorides and the subsequent corrosion of the reinforcing steel and deck deterioration. Very-early strength latex-modified concrete (below ; VES-LMC) was developed in order to realize early-opening-to-traffic bridge deck concrete. Although there has been little research to document the degree of cracking in VES-LMC overlay, there has been a general perception among highway agencies that overlay cracking of VES-LMC, particularly early-age cracking, is a one of problems which should be solved. The purpose of this study was to analyze the cause of map, transverse and longitudinal cracking in VES-LMC and to provide a control methods for minimizing the occurrence of cracks. The proposed prevention against map and transverse cracking was verified by field applications. VES cement was modified, the unit cement contents was reduced into $360kg/m^3$ from $390kg/m^3$, the maximum size of coarse aggregate was increase into 19mm from 13mm, wire mesh and steel fibers were incorporated in concrete mixture.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.695-702
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• 2005

It is known that latex-modified concretes were increased their durability and permeability by added latex. The purpose of this study was to analysis the air void systems in latex-modified concretes using a reasonable and objective image analysis method with main experimental variables such as water-cement ratios, latex contents(0%, 15%) and cement types(ordinary portland cement, high-early strength cement and very-early strength cement). The results are analyzed spacing factor, air volume after hardened, air distribution and structure. Also, air void systems and permeability of latex-modified concretes were compared with correlation. The results are as follows; The same w/c ratio LMC showed better air entraining effect than OPC with AE water reducer. The VES-LMC showed that the number of entrained air below $100{\mu}m$ increased more than four times. In the HES-LMC, micro entraining air having range from 50 to $500{\mu}m$ increased above 7 times without antifoamer. Though spacing factor was measured low, latex-modified concretes were showed that permeability was good. It is considered that air void system does not have an effect on the property of latex-modified concretes but latex film is more influenced in the their durability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1743-1751
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• 2014

It is well known that latex modification can lead to enhancement compressive and flexural performance, tensile bond strength, chloride penetration resistance and freezing-thawing resistance for concrete. For these, many studies for LMC pavement have been widely conducted more than those for conventional pavement concrete. However, due to several problems such as noise and construction cost, new approaches for LMC have been executed to improve the performance of LMC. Recently, Remicon LMC was developed in order to solve the problems of LMC. In this study, the durability of Remcion LMC was compared with latex and mineral additive mixing ratio. From the results, when latex and mineral additive were mixed in Remicon LMC, compressive, flexural and bond strength were satisfied with Korea Highway Construction Guide Specification. And, it showed that the qualitative effect of latex and mineral additive mixing ratio on the durability of Remicon LMC was investigated experimentally. Also, the latex mixed in Remicon LMC must be at least 8%, in order to ensure the durability equivalent or higher than conventional LMC.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.289-292
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• 2006

The purpose of this study was to evaluate a performance of latex-modified repair material applied to the substrate concrete. The experimental variables were latex-cement ratios (5, 10, 15%), polymer(0.5%, 1%) and admixtures. The flow, air content, compressive strength, flexural strength were tested. Test results showed that compressive and flexural strength decreased by adding hydroxyethyl cellulose and increasing water-binder ratio. The compressive and flexural strength were increased when addition of defoamer.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.757-760
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• 2008

The latex modified concrete was applied to baseplate of road bridge after 2000 year. This is in the limelight of stability to be missing problems. But, The baseplate of railroad bridge being experience to difficulty that searching method substituted for bridge waterproofing. In this study, I would like to application on P.C.L layer of railroad bridge using the property and merit of L.M.C. As a result performance test about six item, L.M.C was confirmed no problem to performance and application of bridge waterproofing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.11-12
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• 2014

In this study, fundamental properties of concrete mixed with fiber has been analysed. Compressive strength, tensile strength and plastic shrinkage has been tested to conduct the optimum addition ratio of fiber. Effect to control press concrete's cracking has been tested. The following results could be made as the conclusion. For the flowability, slump decreased about 41-79% when all types of fiber used in the concrete. When the addition ratio of fiber is 1.2%, the slump of concrete decreased about 45%. For the strength properties. all the specimens with different addition ratio of fiber shown higher compressive strength comparing with Plain. Comparing with Plain, cracking decreased when the fiber added. Especially, when NY fiber used in the concrete, the plastic shrinkage did not occurred. In addition, Latex modified concrete(LMC) has improved superior physical and chemical properties. The properties of latex, combined with the low water-cement ratio, produce a concrete that has improved flexural, tensile, and bond strength, lower modulus of elasticity, increased freeze-thaw resistance, and reduced permeability compared to conventional concrete of similar mix design.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.315-320
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• 2002

The effects of slag content and polymer-binder ratio on the strength properties of the polymer-modified concretes using ground granulated blast-furnace slag and a styrene-butadiene rubber (SBR) latex are examined. As a result, the compressive, tensile and flexural strengths of the SBR-modified concretes using slag increase with increasing polymer-binder ratio and slag content, and maximized at a slag content of 40 ％. In particular, the SBR-modified concretes with a slag content of 40 ％ provide approximately two times higher tensile and flexural strengths than unmodified concretes. Such high strength development is attributed to the high tensile strength of SBR polymer and the improved bond between cement hydrates and aggregates because of the addition of SBR latex.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.5
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• pp.153-160
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• 2019

The purpose of this study was to investigate the mechanical and durability characteristics of latex-modified concrete using ultra rapid hardening cement : four types of mechanical tests including compressive strength, modulus of elasticity, flexural strength and bond strength were performed; and seven types of durability tests including resistance of concrete to chloride ion penetration, freeze-thaw resistance, scaling resistance, coefficient of thermal expansion, cracking tendency, abrasion resistance and drying shrinkage were performed. Required material performance of each test was determined in accordance with the Korea specification for repair of concrete and pavement repairing materials. The test results satisfied the required material performances, and presented a good mechanical and durability characteristics. In particularly, the materials showed early development of compressive strength, flexural strength and bond strength at 3 and 4 hours after curing. SEM photos were also taken to investigate the micro structures of the materials after chloride ion penetration test.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.569-572
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• 2006

This study was performed to investigate the characteristics of carbonation for latex modified concrete with fly ash and blast furnace slag. The experimental variables consisted of ground granulated blast-furnace slag contents (0%, 30%, 50%), fly ash contents (0, 30%) latex contents (0, 5, 10, 15%). Two different methods of carbonation test such as $CO_2$ gas and 5% sulphuric acid digestion resistance test were varied in this study.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.355-360
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• 2002

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid- setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as the basic for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMM and RSLMC. Chloride ion permeability test was carried out to estimate water permeability resistance. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235kgf/cm$^2$ and 49kgf/cm$^2$, respectively, which exceeded the flexural strength criterion of 45kgf/cm$^2$ in order to open the RSLMC placed to traffic. The chloride permeability using A and C antifoamer at 28 days were below 100 coulombs, which was the permeability rating of negligible according to ASTM.