Reinforced concrete hume pipes have been widely used as drain pipes. However, many reinforced concrete hume pipes are exposed to the deteriorated environments such as freezing-thawing damage, chemical attack and chloride ion immersion by using sea sand. The purpose of this study is to improve the durability of reinforced concrete hume pipe by using the polymer cement slurry(PCS)-coated rebar and treating the surface by polymer cement mortar(PCM). From the test results, it is apparent that PCS-coated rebar has a excellent resistance to chloride ion penetration and the PCM has good mechanical properties and durability as a lining material for reinforced concrete hume pipe product.

An experiment was conducted to recycle sulfur which is industrial by-product, by producing concrete mix materials. production of specimens were implemented on the replacement of modified sulfur emulsion with cement. this paper presents data on the experimental results of durability test of the each specimens.

In this research we carried out the compressive strength, modulus of rupture and scaling resistance tests in order to evaluate the durability of concrete pavement containing waste glass powder. As a results of this research, the concretes incorporating 20% waste glass powder had higher compressive strengths and modulus of ruptures than the concretes with 20% fly-ash. Also, they had a better scaling resistance than ordinary portland cement concretes and fly ash concretes.

In this study, degradation due to the durability of the coating to reduce the check for to determine the deterioration of the durability coating was in parallel to outdoor exposure test and the salt spray test on the marine environment. weatherability paint coating was electrochemical measured using EIS (Electrochemical Impedance Spectroscopy) to evaluate durability. The purpose of the study was to compare the reduced durability of the paint coating.

SUPER concrete poontoon is developed to overcome shortcomings about corrosion problem of steel poontoon and the insufficient freeboard line of concrete poontoon. The top slab resists for truck load or sidewalk live load. And the soffit slab and outer wall resist for horizontal and lift components of wave pressure. The optimum characteristic compressive strength of SUPER concrete poontoon is analyzed 100Mpa. SUPER concrete poontoon have advantageous durability compared with the steel or general strength material in a lot of Chloride Exposure at offshoer, These are checked by Fick's diffusion curve and depth of neutralization. Finally, SUPER concrete is alternative material for steel and concrete poontoon.

The recent revision of Housing Act allow vertical extension up to maximum 3 stories and increase the ratio of floor area to site up to 15%. Currently, the feasibility of performing vertical extension is evaluated based on safety diagnosis provisions and manuals for vertical extension with preliminary investigations on slope, deflection, load-bearing capacity, and durability. However, a need for more reasonable evaluation methodology for the preliminary investigation is still required because the current procedures are borrowed from safety diagnosis provisions and manuals for reconstruction without detailed examinations on evaluation criteria and sampling methods. Accordingly, this study is intended to suggest a method to obtain feasible sampling numbers for durability assessment by analyzing field data on concrete carbonation, chloride content, and steel corrosion. The results of this study are expected to be beneficial for establishing more reasonable field sampling number, and in turn, more reliable durability assessment protocol for vertical extension.

콘크리트 구조물의 내구성을 향상하기 위해 개발된 통기성이 개선된 나노합성 폴리머 표면처리제를 도포한 콘크리트의 내구성향 상 효과를 평가하기 위해 내부 구조와 공극량을 측정하였으며, 염분침투, 탄산화, 동결융해 및 화학적 침식 저항성에 대한 실험을 진행하여 기 존 표면처리제와 비교․분석하였다. 공극량과 내부 구조를 측정한 결과, 나노합성 폴리머 표면처리제를 도포한 콘크리트는 0.3㎛ 이상의 공극과 0.1㎛ 이하의 공극영역에서 세공량이 감소하는 경향을 보였으며, 전자현미경을 통한 촬영된 내부는 수화조직에 의해 치밀함을 보였다. 나노합 성 폴리머 표면처리제를 도포한 콘크리트의 염분침투 깊이는 무도포 콘크리트에 비해 약 92% 이상, 수성 에폭시 표면처리제를 도포한 콘크리 트보다도 약 70% 이상 감소하였다. 이는 탄산화, 동결융해 및 화학적 침식 저항성 실험에서도 비슷하게 나타났다. 특히 황산 5% 수용액에 침지 실험한 화학적 침식 저항성 실험에서는 침지 12일 이후 무도포 콘크리트와 수성 에폭시 표면처리제를 도포한 콘크리트에서 -4%의 중량감소를 보였지만, 나노합성 폴리머 표면처리제를 도포한 콘크리트는 -1.7%의 중량감소율을 보였으며, Tsivilis et al.에 의한 외관등급 조사법에서도 우 수한 결과를 보였다.

본 연구에서는 유황을 폴리머화하여 콘크리트 표면보호재로 활용가능성을 검토하기 위하여 내구성능 및 생물독성 평가를 실시하 였다. 평가 결과, 콘크리트 표면보호재의 내화학성능은 산, 알칼리 용액에 대하여 화학저항성이 우수한 것으로 나타났다. 배합조건별 촉진내후 성 실험 후 부착강도평가 결과 규사분말 및 플라이애시를 동시에 혼합한 배합에서 가장 우수한 강도특성을 나타내었다. 콘크리트용 표면보호 재 시험체의 온냉반복 후에도 모든 배합조건에서 부착강도 1 MPa을 상회하였고, SFS배합에서 가장 높은 부착강도를 나타내었다. 표면보호재 를 도포한 콘크리트의 촉진탄산화 및 염소이온침투저항성을 검토한 결과, 규사분말을 채움재로 사용한 표면보호재를 도포한 시험체에서 가장 우수한 내구성능을 나타내었다. 유황폴리머를 콘크리트 표면보호재로 사용시 생물독성 검토를 위해 어독성 실험을 수행한 결과, 유황폴리머 는 생물에 미치는 영향은 없는 것으로 나타났다. 표면보호재의 내화학성, 동결융해저항성, 탄산화, 염소이온침투저항성 등을 모두 고려하여 볼 때, 본 연구범위에서는 유황폴리머에 채움재로서 규사분말과 플라이애시를 각각 20%씩 대체하는 것이 적절한 수준인 것으로 판단된다.

This paper presents a comprehensive probabilistic model of reinforcement corrosion initiation under the combned action of carbonation and chloride ingress. The numerical results show that the probability of reinforcement corrosion initiation under the combined action is much higher than the case of only considering the action of single factor.

This study is carbonation resistance of the natural durability enhancement materials that can reduce cracking of the concrete. The durability enhancement materials of natural were substituted 10%, 20%, 30% of cement, the results were confirmed excellent carbonation resistance as the more increasing the natural durability enhancement.

Based on the study of chloride migration coefficient and hydration heat evolution, it was found that the use of ternary blended cement was effective to achieve desired service life and minimum crack index. On the other hand, a high level of compressive strength is required for marine concrete mix design.

This paper was examined the durability properties of concrete using rapid cooling slag as fine aggregate for concrete. The results of experiments, concrete using rapid cooling slag showed that durability properties was equal to concrete using normal fine aggregate.

Large construction such as tunnel elements and foundations for bridges can be placed on large sea water depths where the water pressure is fairly different from the pressure in the splash zone although main driving force of chloride penetration in concrete have been regarded as diffusion. Moreover, hydrostatic pressure increases in proportional to measured depth from the surface of water because of the increasing weight of water exerting downward force from above. In this study, new experiment method to estimate chloride penetration of concrete under water pressure is introduced. The life length for such a concrete structure on a large sea water depth is estimated using the normally used models and this experimental program.

A new approach to evaluate the durability of concrete structures was proposed in this study, which additionally considered the time-dependent and environmental effects, especially freezing-thawing and salt attack. This might have a potential for the reasonable durability evaluation with the systematic management of SOC facilities.

For a efficient maintenance it is necessary to inspect SOC infrastructure using the performance-based evaluation method throughout quantitative measurement. In this study durability evaluation factors of steel structural member are proposed in order to develop performance-based evaluation method of SOC infrastructure.

본 연구에서는 압축강도 24MPa 이상 열전도율이 기존 콘크리트보다 2배 감소된 구조용 단열성능 향상 콘크리트를 개발하고 현장적용 하기 위한 실험을 진행하였다. 슬럼프 및 공기량 시험결과 Plain과 규조토 미분말을 사용한 배합은 경과시간에 따라 슬럼프와 공기량 저하 가 나타났으며, 마이크로기포제를 사용한 배합은 슬럼프와 공기량 저하가 나타나지 않았다. 또한 단열성능 향상 재료를 사용한 배합의 단위 용적질량은 Plain 대비 감소하였다. 압축강도는 단열성능 향상 콘크리트가 Plain보다 감소한 결과를 나타내었으나 목표강도 24MPa를 만족 하였으며, 열전도율은 Plain보다 감소하는 경향을 보였다. 단열성능 향상 콘크리트의 동결융해 저항성은 Plain과 유사하였고, 중성화 저항 성은 규조토 미분말을 사용한 배합이 재령 4주에 Plain과 유사했으며, 마이크로기포제를 사용한 배합은 Plain보다 중성화 저항성이 저하되 었고, 길이변화율은 Plain보다 전체적으로 증가되었다.

Analyzing the change of concrete pore structure due to carbonation and, also, considering the decrease of chloride binding capacity and the release of combined chloride ions, we established a comprehesive theoretical model which can reflect the influence of carbonation on chloride transport.

The durability evaluation method of concrete structures was introduced. It is divided into two parts, one is aging environment, and the other is aging development evaluation which including time factor. This method will be helpful to estimate the synthetic durability of the SOC facilities.

This study is the study of the strength characteristics of the study of the natural durability enhancement materials that can reduce cracking of the concrete. The durability enhancement materials of natural were substituted 10%, 20%, 30% of cement, the results were confirmed excellent strength as the more increasing the natural durability enhancement.