콘크리트는 우수하고 뛰어난 내구성에 의해 구조물 건설에 가장 많이 사용되는 재료 중 하나이다. 오늘날 급격한 경제의 발전 및 도시화 등에 의해 오늘날 구조물은 대형화 및 고층화되고 있다. 이에 따라 고강도, 고경량, 고내구 콘크리트 개발에 대한 다양한 연구가 진행되고 있다. 특히 나노소재가 첨 가된 콘크리트는 나노소재에 의해 미세공극이 충진되어 강도 및 내구성이 우수한 것으로 알려져있다. 그러나 기존 나노소재가 적용된 콘크리트는 단위중량이 높아 이를 구조물에 적용시 자중을 증가시키 는 단점이 있다. 이에 본 연구에서는 입자 직경이 10-100 μm이지만 입자 내부의 공극이 있어 단위 중량이 0.6t/m3인 Micro hollow sphere가 잔골재로 사용된 고경량, 고강도 콘크리트의 염화물 침투 특성을 평가하였다. 본 연구에서 사용된 실험변수로써 Micro hollow sphere의 잔골재 치환량(0%, 42%, 100%)가 고려되었으며, 이 시편의 단위중량은 각각 2.37 t/m3, 1.89 t/m3, 1.62 t/m3이다. Micro hollow sphere가 사용된 콘크리트의 염화물 침투 특성은 NT-Build 492 시험을 통해 평가되었다. 실 험결과 Micro hollow sphere 치환율이 0%, 42%, 100%인 실험체의 단위중량은 염화이온 확산계수는 각각 4.45 x10-13 m2/s, 2.57 x10-13 m2/s, 1.4x10-13 m2/s로 Micro hollow sphere 치환량이 증 가함에 따라 염화이온 침투 저항성이 증가하는 것으로 확인되었다. 따라서, Micro hollow sphere를 이용한다면 단위중량이 작으며 내구성이 큰 고경량, 고내구 콘크리트 배합이 가능할 것으로 판단된다.

The purpose of this experimental study is to chloride ion penetration resistance performance of concrete using Nano-TiO2 Carrier. As a result, concrete using Nano-TiO2 Carrier was confirmed to be superior than ordinary concrete and commercial TiO2 concrete chloride ion penetration resistance performance.

Recently, a great social damage has been caused by the sargassum homeri, which has flowed from China in the Jeju and Namhae coasts. In this study, biopolymer was prepared by using sargassum homeri and applied to bridge pavement concrete. The performance of chloride ion penetration resistance of the bridge pavement concrete made of biopolymer was evaluated. As a result, excellent penetration resistance performance was shown.

In this study, chloride penetration resistance and electrical resistivity properties of concrete using industrial waste were evaluated. From the results, the chloride diffusion coefficient increases and electrical resistivity decreases when electric furnace slag is mixed. It is needed that the comparison of results with long-term because the electric furnace slag has a ferrous component.

In this study, the effect of calcium leaching on chloride ion penetration resistance of mortar specimens was evaluated. According to test results, the penetration depth of chloride ion was increased after the calcium leaching attack.

This research provides optimization techniques for concrete mixture design for chloride penetration performance and cost. For optimization, objective functions are constructed with variables representing factors used in concrete mixture design process. Multi Objective Harmony Search Algorithm (MOHSA) is used for optimization and the result gives relationship between concrete’s chloride ion diffusivity and cost.

해양 콘크리트 구조물 중 침지대에 위치한 구조물은 수심이 10 m 깊어질수록 1 atm의 정수압을 받아 염화물이온 침투가 촉진될 가능성이 있다. 본 연구에서는 정수압이 해양콘크리트의 염화물이온침투에 미치는 영향과 원인을 평가하기 위하여 보통 포틀랜드 시멘트와 고로슬래그 시멘트를 활용한 콘크리트를 각각 1, 6 atm의 정수압과 인공해수에 노출시켜 깊이별 수용성 염화물량과 미세구조 분석을 실시하였다. 측정결과 6 atm의 정수압을 받는 콘크리트는 표면 염화물이온 농도가 급격하게 상승하며, 깊이별 수용성 염화물량이 증가하는 경향을 나타내었다. 또한, 정수압을 받은 콘크리트는 5~100 nm에 해당하는 모세관공극이 증가하는 경향을 나타내었다.

본 연구에서는 표면 침투 및 코팅형 흡수방지재인 Polydimethylsiloxane(PDMS)을 고인성 섬유복합체(ECC)에 적용하여 적용성, 강도 평가 및 염화물이온 침투 저항성능에 대한 연구를 수행하였다. PDMS 적용 방법에 따른 침투깊이를 분석한 결과 모든 방법에서 KS F4930 의 기준을 만족하는 것을 확인하였다. 적용 방법 중, 침지 방법이 가장 우수한 침투깊이를 보였으나 현장적용성을 고려할 경우 스프레이 방법이 적용 가능한 것으로 확인되었다. ECC 배합에 따른 PDMS 침투깊이 실험 결과 배합강도가 감소할수록 침투깊이는 최대 70% 이상 증가하는 경향을 나타났다. 압축강도 시험 결과에서는 PDMS 침투 깊이가 큰 M4-A, M4-B 시험체의 압축강도는 PDMS를 적용하지 않은 M4 시험체와 비교하여 9.6%, 8.0% 압축강도가 감소하였다. 또한, 침투깊이가 작은 M1-A와 M1-B 시험체의 압축강도는 M1 시험체와 비교하여 4%, 2.2% 감소하여 PDMS 침투깊이가 클수록 강도감소율이 증가하였다. 염소이온침투 저항성능 평가 시험결과, PDMS의 침투깊이가 클수록 염소이온 침투 저항성능이 향상되는 것을 확인하였다.

This study is to perform experiment of concrete according to addition of blast furnace slag powder and sulfur activator dosages. Blast furnace slag powder used at 30, 50, 80% replacement by weight of cement, and liquid sulfur additives was chosen as the alkaline activator. As a result, it should be noted that the sulfur alkali-activators can not only solve the disadvantage of blast furnace slag concrete but also offer the chloride resistance of alkali-activated blast furnace slag concrete to blast furnace slag concrete.

This study was evaluated the chloride penetration resistance performance of Surface Protection Material(SPM). SPM was applied 0.25 and 0.51 kg/㎡ to the surface of the mortar and immersed aging of the chloride solution 7, 14, and 28 days. As a results, In the case of SPM was applied, chloride did not penetrate until the 28th day.

In this study, the resistance of chloride penetration and sulfate attack of mortar substituted heavyweight waste glass were evaluated. As a result, chloride penetration depth and diffusion coefficient decreased with the substitution of waste glass, chloride penetration resistance is increased. For sulfate attack resistance, the effect of heavyweight waste glass was little.

In this study, the absorption protection agent was applied to the surface of fiber reinforced concrete to evaluate the chloride ion penetration resistance. The evaluation was based on the method presented in KS F 2711. It was confirmed that the resistance performance against chloride ion was improved by 56∼71% when the coating material was applied.

In this study, poly-silicon sludge was used in replacement with Portland cement as SCMs. Poly-silicon sludge has an ability to improve the durability to the concrete system. Thus, the chloride penetration test of PS specimens was conducted for the confirmation of the durability. From the results, The penetration depth of the plain specimens is deepest, and gradually decreases as PS substitution rate increases.

In this study, chloride penetration in a repaired concrete using magnesium polymer ceramic (MPC) was assessed based on the NT BUILD 492. To investigate the effect of repaired material on chloride penetration, a cylinder OPC concrete specimen was fabricated and attached on the surface with MPC. Then, chloride penetration test was carried out on the combined concrete sample at a constant applied voltage (30 V) for 6 hours. It was found that most of chloride sources was passed though the interface between OPC and MPC, resulting in a loss of chloride in the material. Thus, it is needed to modify the conventional chloride penetration test for the repaired concrete specimen.

The chloride penetration characteristics of concrete exposed to the marine environment were evaluated by chloride migration coefficient and the surface chloride content, and characteristics of the marine environment such as spray zone and tidal zone are considered

From the test results, it was found that the compressive strength and the resistance of chloride ion penetration were evaluated the slag content of the concrete for bridge pavement. Compressive strength test results showed that initial strength was decreased as slag replacement ratio increased. The chlorine ion penetration performance increased with increasing strength.

The effect of loading on chloride penetration into concrete is evaluated in this study. It is found that the chloride pene- tration rates for OPC concrete and blast furnace slag BFS concrete under the tensile stress were increased by 29% and 77%, respectively. The diffusion coefficient of FA and BFS concrete was lower than that of conventional concrete without BFS, no loads and stress states. Under tensile stress, the diffusion coefficient for FA and BFS, plain concrete showed higher values with increasing stress. The influence of specific surface area on the diffusion coefficient was investigated. As a result, the larger the specific surface areas of BFS are the lower diffusion coefficients. This tendency was more pronounced under the high stress conditions. The chloride penetration depth was distributed uni- formly when no stress was applied. However, in the case of tensile loading, the diffusion depth was not distributed uni- formly, and showed prominent characteristics. This result indicates that analysis using average values of chloride pene- tration depth is not proper under load conditions.

The chloride penetration characteristics of concrete exposed to the marine environment were evaluated by chloride migration coefficient and the surface chloride content, and characteristics of the marine environment such as spray zone and tidal zone are considered. 요

From the test results, it was found that the compressive strength and the resistance of chloride ion penetration were evaluated the slag content of the concrete for bridge pavement. Compressive strength test results showed that initial strength was decreased as slag replacement ratio increased. The chlorine ion penetration performance increased with increasing strength.