• 콘크리트학회지
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• 제9권6호
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• pp.185-193
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• 1997

본 연구는 각종 제진재료를 이용하여 진동을 억제할 수 있는 콘크리트를 개발하여 각종 건설공사에서 흔히 발생할 수 있는 진동공해문제를 억제하고자 하며 아울러 폐기물의 재활용차원에서 폐자재를 이용하여 유용한 제진콘크리트를 개발하고자 하는데 그 목적이 있다. 우선, 제진재료를 이용한 압축강도 (200kg/$\textrm{cm}^2$)이상의 콘크리트 배합비를 찾기 위하여 24배치의 예비실험을 수행하였으며, 선정된 적정배합비에 따른 제진재료를 이용한9개의 진동시험체보를 제작하여 보의 구조적 및 재료적 동적특성 즉 1차 공명진동수와 동적 휨강성 및 감쇠비를 측정하여 제진효과를 조사하였다. 그리고 압축강도에 의한 각 시험체의 균열모멘트를 추정하여 재하하중과 균열모멘트비(M/Mcr)에 따른 하중단계별 동적특성값을 살펴보았다. 제진재료로서는 라텍스(Latex), 고무분말(Rubber Powder)그리고 플라스틱 레진( Plastic Resin)등을 사용하였고, 재료적, 구조적 진동감쇠효과를 파악하고자 KS F2437규정과 진동파의 속도법을 사용하였으며, 감쇠비 측정은 Frequency Spectrum 곡선에 대한 Polynomial Curvefitting 방법과 기하학적 해석방법을 이용하여 각각의 결과를 비교.분석하였다.

• 산업기술연구
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• 제24권A호
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• pp.165-171
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• 2004

Latex modification of concrete provides the material with higher flexural strength, as well as high bond strength and reduced water permeability. However, If the thermal expansion properties of overlay concrete (latex-modified concretes) are big different from that of substrate (ordinary portland cement concrete), these would cause a big interfacial stresses and result in premature failure. Therefore, the purposes of this study were to investigate thermal expansion characteristics of latex-modified concrete with cement types. The result of thermal expansion showed the coefficient of thermal expansion of concretes increased with latex inclusion. The coefficient of thermal expansion of RSLMC was a little smaller than that of LMC, which might be due to the finer cement grain, compacter internal, and stiffer properties of concrete. However, the coefficients of LMC and RSLMC were quite similar to that of ordinary cement concrete. Thus, this would not cause an interfacial stresses and will enable to ensure long-term performance of concrete bridge deck overlays.

• 산업기술연구
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• 제23권A호
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• pp.157-163
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• 2003

The properties of mechanics and durability of LMC have been performed actively. However, little studies on analysis and properties of thermal expansion has been on the temperature variation. Especially, the low of bonding strength and tensile cracking are caused by difference of thermal expansion between LMC and the substrate concrete. Therefore, this study focused on effect of thermal expansion behavior and properties of LMC according to temperature variation. To identify the property of thermal expansion of LMC, tests of modulus of thermal expansion were carried out at 28 days after casting specimen, subjected to temperature variation between $10^{\circ}C$ and $60^{\circ}C$. The results of this study showed the modulus of elastic of LMC was similar to that of ordinary portland concrete(OPC). It means that stresses caused by difference of modulus of elastic did not occur on interface between LMC and existing concrete. The modulus of thermal expansion of LMC had a little smaller than that of OPC. The modulus of thermal expansion of polymer modified concrete is generally larger than OPC, but the result of this test is disagree with the fact, which may be due to the humidity evaporation difference and aggregate properties.

• 산업기술연구
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• 제27권A호
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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.

• 산업기술연구
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• 제25권A호
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• pp.49-56
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• 2005

Recently, very-early strength latex-modified concrete(below ; VES-LMC) has been developed for repairing and overlaying the old concrete bridge deck. VES-LMC provides the advantage of very-early-strength, as well as high flexural strength, bond strength, durability, resistance to corrosion, reduced water permeability and resistance to damage from freeze-thaw cycles. The compressive and flexural strength of VES-LMC are 21 MPa and 4.5 MPa at 3 hours after concrete placing, respectively. However, VES-LMC would have a relatively large shrinkage at early-age because of reduced water-cement ratio, big water self-dissipation, and rapid hydration reaction. Therefore, the purpose of this study was to evaluate the early-age and restrained shrinkage of VES-LMC, having an experimental variables such as latex contents and cement types. The latex contents included 0%, 5%, 10%, 15% and 20%, and the cement types included ordinary portland cement and very-early strength cement.

• 대한건축학회논문집:구조계
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• 제35권5호
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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.

• 콘크리트학회지
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• 제8권6호
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• pp.163-172
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• 1996

최근 많은 양의 폐타이어가 발생됨에 따라 사회적 문제로 대두되고 있는 실정이며, 이에 대한 재활용은 각 분야에서 활발하게 연구되고 있다. 건설 분야에서는 폐타이어를 냉각 분쇄하여 만든 분말을 시멘트 콘크리트에 혼입하여 사용하는 연구가 많이 수행되고 있다. 시멘트 콘크리트에 폐타이어 분말을 혼입하여 사용할 때는 폐타이어 분말과 시멘트경화체 사이에서 접착성의 문제로 기초적 성질이 저감된다. 본 연구에서는 시멘트 모르터 내부에서 폐타이어 분말의 접착력을 증진시키기 위하여 시멘트 혼화용 폴리머 중의 하나인 스티렌 부타디엔 고무(SBR)라텍스를 사용하여 기초적 성질을 개선하고자 하였다. 실험결과 SBR 코팅 폐타이어 분말을 혼입한 시멘트 모르터는 코팅하지 않은 폐타이어 분말을 사용한 경우보다 기초적 성질이 개선되는 것으로 나타났으며, 또한 폴리머 시멘트비 10%를 사용한 SBR 라텍스 혼입 폴리머 시멘트 모르터의 경우에도 기초적 성질이 개선되었다.

• 산업기술연구
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• 제21권B호
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• pp.301-306
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• 2001

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a same controlled environment of 60% of relative humidity and $20^{\circ}C$ of temperature. Test results revealed that the drying shrinkage of latex modified concrete(LMC), rapid-setting cement latex modified concrete(RSLMC) was considerably lower than that of ordinary portland cement concrete(OPC), rapid-setting cement concrete(RSC), respectively. This may be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic and colloidal properties of the latexes, resulting in reduced water evaporation.

• 산업기술연구
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• 제21권B호
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• pp.317-324
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• 2001

This study focused on the investigation of strength development and permeability of LMC(Latex Modified Concrete) and RSLMC(Rapid-Setting Cement Latex Modified Concrete) as the latex content, cement types and w/c ratio changed. The compressive strength of latex modified concrete decreased slightly and the flexural strength increased quitely at 15% of latex content. This may be due to the flexibility of latex filled in voids and interconnections of hydrated cement and aggregates by a film of latex particles, respectively. The permeability test results showed that the permeability of LMC was considerably lower than that of conventional concrete. Results of chloride permeability test, for RSLMC indicated very low at an early age caused by the early formation of needle-shape ettringites and latex film.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4635-4642
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• 2010

라텍스로 개질된 콘크리트는 높은 휨강도 뿐만아니라 부착강도 및 투수저항성이 좋은 재료특성을 제공한다. 이러한 이점을 활용한 초속경 라텍스개질 콘크리트(VES-LMC)에 관련된 연구결과는 재료에 관한 것이 대부분으로, VES-LMC로 덧씌우기 보강된 RC 보의 부착 경계면 거동특성에 대한 체계적인 연구는 미진하다. 따라서 본 논문에서는 VES-LMC로 보강된 철근콘크리트 보의 비선형 휨 거동에 대한 특성을 알아보고자 ABAQUS를 매개변수 연구를 수행한 결과 다음과 같은 결과를 얻을 수 있었다. 비선형 휨 해석을 위하여 본 논문에 적용된 모델의 적합성 여부를 확인한 결과 실험값과 비교적 유사한 경향을 보이는 것을 확인 할 수 있었다. 두께가 증가함에 따라 최대 저항강도가 증가하는 경향을 보여주었으며, 또한 강성 이 증가하여 내하력이 증진되는 결과를 확인할 수 있었다. 부착강도를 변수로 해석한 결과, 전단강도가 증가함에 따라 휨 저항능력이 향상되는 결과를 확인 하였으며, 두 이질재료의 부착능력이 구조물의 내하력에 지배적인 인자로 작용하는 것을 알 수 있었다.