• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.313-317
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• 2003

The study is the results of accelerated tests and the specimens, mortars, are submerged in a 5% sulfuric acid solution. The deterioration of specimens is followed up by investigating the change in weight and compressive strength of the specimens and techniques such as XRD and XRF are used to examine the chemical changes. Sulfuric acid is a very aggressive acid that reacts with the free lime [$Ca(OH)_2$] in the concrete forming gypsum($CaSO_{4}.2H_{2}O$). This reaction is associated with an increase in volume of the concrete, and the corroded surface becomes soft and white. The results showed that the OPC mortar caused an decrease in weight above 18% and strength loss about 57%. On the other hand, AASC(alkali-activated slag composites) did not cause any decrease in weight and in the case of strength caused an decrease below 10%. In addition, this mechanical results was verified to XRD and XRF.

• 한국농공학회논문집
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• 제57권4호
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• pp.11-19
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• 2015

The important properties of EVA (ethylene vinyl acetate) redispersible polymer was waterproof, densification of internal pore space of concrete and ball bearing and micro filler. Also, the significant role of polypropylene(PP) fiber was crack control and blockade of movement for deterioration factors. The most studies for EVA were limited in the field of mortar and PP fiber reinforced concrete had been studied in the state of being restricted unit water content, rich mix and mixing much of the fiber without considering construction site. Therefore, the control mix design were applied in ready mixed concrete using 10 % fly ash of total cement weight used in batch plant. On the basis of control mix design, EVA contents ranging from 0 % to 10 % of total cement weight and PP fiber contents ranging from 0 % to 0.5 % of EVA concrete volume were used in the mix designs. The results showed the maximum compressive strength value was measured at EVA 5.0 % and PP fiber 0.1 %, the minimum water absorption ratio was at EVA 10 % and PP fiber 0 %, the durability factor for freezing and thawing resistance was at EVA 5.0 % and PP fiber 0.3 % and the minimum weight reduction ratio of resistance to sulfuric acid attack was at EVA 10 % and PP fiber 0.5 % after curing age 42days. Meanwhile, From these results, PP fiber reinforced EVA concrete would be very benefit, if each optimal mix types were used in hydraulic structures, underground utilities and agricultural structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.421-424
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• 2008

본 연구에서는 산 및 황산염 저항성에 미치는 시멘트 종류의 영향을 평가하기 위하여 물-결합재 비 32% 및 43%에 대해서 보통 포틀랜드 시멘트(OPC), 2성분계 시멘트(BBC), 및 3성분계 시멘트(TBC)와 같은 3종류의 시멘트를 사용한 콘크리트 공시체를 제작하였다. 제작된 콘크리트 공시체에 대해서 JSTM C 7401에 따라 5% 황산, 10% 황산나트륨 나트륨 및 10% 황산마그네슘 용액에 의한 침지실험을 통하여 재령에 따른 외관 변화 및 질량 감소율을 평가하였다. 재령 91동안의 침지실험 결과로부터, 콘크리트의 산 및 황산염에 대한 저항성은 물-결합재비가 감소할수록 증가하고, BBC와 TBC 콘크리트가 OPC 콘크리트보다 우수한 것으로 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제14권3호
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• pp.171-177
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• 2010

콘크리트 구조물은 시간 경과에 따라 화학적인 물질에 노출되거나, 염해, 중성화 등으로 인하여 콘크리트표면 결손 등이 발생하고 이에 따라 수명이 단축되는 현상이 발생할 수 있다. 특히 황산염 침식의 경우 표면 결손이 급격하게 발생하고 이에 따른 수분의 침투에 의하여 보강 재료로 사용되는 철근의 부식이 발생함에 따라 구조적으로 안정성이 하락하는 특성을 보이고 있다. 본 연구는 시멘트계 보수재의 가장 큰 단점중의 하나인 내산성의 문제점을 해결하기 위하여 알루미노실리게이트를 적용한 내산모르타르에 관한 물리적 특성을 시험을 통하여 연구하였으며 시험결과 압축강도 및 휨강도의 경우 동등한 강도를 발현하였으며, 황산용액에 침지하여 중량변화를 관찰한 내산성의 경우 시멘트계 단면복구재가 80% 이상의 중량 변화를 나타내는 반면 시험시료의 경우에는 4% 정도의 중량결손이 발생하여 내산성에 효과적인 특성을 가지는 것으로 나타났다. 따라서 알루미노실리케이트류를 첨가한 내산 모르타르의 특성이 우수한 것으로 나타나 산에 의한 침식 등이 우려되는 곳에 단면복용재료로서 효과적인 특성을 발휘할 수 있을 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.84-85
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• 2015

The aim of this study is to develop crack self-healing concrete and repair materials with the sulfate resistance using geo-materials and by-products for practical industrial application. Research has been done on the healing of cracks in aged concrete, but it seems that very little is known about the actual healing mechanism and its conditions. In this research, the essential properties of geo-materials with pozzolanic reaction for self-healing were analyzed and discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.249-252
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• 2006

Recently, as it has greatly increased the demand on the serviceability of subway, cable tunnel and underground storage, the stability of tunnel structures has been attracting the concern of engineers and researchers. Thus the aim of the present study is to evaluate acid attack resistance of shotcrete using in tunnel structures. And, in order to understand the deterioration mechanism, test using scanning electron microscopy(SEM) analysis and X-ray diffraction showed that the deterioration mechanism due to acid attack in shotcrete.

• 한국농공학회지
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• 제13권3호
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• pp.2313-2321
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• 1971

• 한국농공학회지
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• 제13권2호
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• pp.2225-2254
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• 1971

• 한국농공학회지
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• 제13권2호
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• pp.2255-2261
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• 1971

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술대회지
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• pp.71-76
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• 2004

This paper investigate that the effect of the concrete containing mineral admixtures(pozzolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for $3\sim4$ replacement ratios under W/B ratios ranged from 0.40 to 0.55. Specimens were immersed in $3.6\%$ NaCl solution for 330 days, and penetration depth, water soluble chloride contents and acid soluble chloride contents were measured in 28, 91, 182 and 330 days. Then, diffusion coefficient were calculated using total chloride contents. As a results. the kinds of mineral admixture and replacement ratios had a great effect on the resistance property of the concrete to chloride ion invasion compared with the plain concrete. And the optimal replacement ratios of mineral admixture had a limitation for each admixtures. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures and the penetration depth from the concrete skin. Chloride diffusion coefficient of each concretes decreased with the time elapsed. and the diffusion coefficients of the concrete immersed salt water for 330 days had a establishment with the compressive strength measured before immersing.