Recently, in Seoul there is a growing interest in the L type gutter between the street and the sidewalk because the broken gutter spoils the appearance of the city. The gutter has been viewed as an unimportant attached facility of the road despite an important drainage facility. Also, the gutter lost function by various deterioration actions is becoming hideous objects of streets. Accordingly, many engineers recognized problems about the gutter and tried to seek for solution. In this study, we desired to confirm that the inside of the gutter concrete was not deteriorated even if the surface of the gutter concrete was deteriorated by the de-icing salts. We could obtain thirty core specimens deteriorated by de-icing salts in Seongbuk-gu which is old downtown, has many hills such as Arirang-Hill, Miari-Hill, etc. in Seoul and test compressive strength. It was confirmed that the compressive strength of the gutter concrete follows normal distribution and it is statistically significant 1% level that the population mean of the compressive strength of the gutter concrete is more than 18MPa.

This study was evaluated compressive strength of age 28 days of binary blended concrete according to there type of superplasticizer and there type of w/c. In addition, we are proposed modification prediction model equation that can reflect efficiency of water reducing and influence of binders using Lyse equation to predict the compression strength through the conventional W/C.

This study was investigated the influence of increase in compressive strength according to water reducing ratio. As a result of the analysis, it is determined that compressive strength according to water reducing ratio was increased by increasing the efficiency of cement.

In order to identify the nature of recycled fine aggregates, an experiment was conducted by mixing recycled fine aggregates. Then, comparative analysis was carried out throughout compressive strengths obtained from steam curing and water curing methods. The concrete mixed with recycled fine aggregate has low strength gain compared to the conventional concrete. But in case that concrete produced in dry process is applied to precast concrete prod

Effects of recycled fine aggregate on the behavior of cement-based concrete were evaluated with different compressive strengths through experiments. It can be observed that recycled fine aggregate can be useful to fabricate precast concrete products in terms of having of concrete strength equivalent to natural aggregate.

In this study, chloride penetration of calcium leached concrete according to mineral admixture ratio were compared with OPC. From the results, it showed that chloride diffusion coefficient in calcium leached concrete were increased as calcium leaching period increase. However, the chloride diffusion coefficient of BFS case showed the better resistance than Fly Ash case. And, the distribution of chloride diffusion coefficient was significantly changed by calcium leaching period.

Fracture behavior of concrete subjected to dynamic loading is affected by loading rate and strain rate. In this study, compressive strength properties according to strain rate of fiber reinforced concrete by rapid loading with 500ton rapid loading test machine was analyzed.

Recently, the concern on the deterioration of concrete due to de-icing salts and its counter measurements has been increased. This paper discusses the results from investigation of pre-mature deteriorated existing road-subsidiary concrete structures and the specification of concrete quality.

Traditional methods for concrete structure demolition is not adequate specially for urban areas and historical places due to hazard of explosive and noise. Therefore, Soundless Chemical Demolition Agents (SCDA) is useful in urban area and historical places. In this study, a analysis for SCDA is performed depending on boundary conditions.

FRP에 대한 많은 연구가 진행상에 있으나 대부분 전단강화 효과에 중점을 두고 있다. 본 연구는 FRP RC 요소에 외부적으로 FRP Uwrap의 고정 효과에 중점을 두고 Uwrap의 거동에 영향을 주는 변수를 체계적으로 평가하였다.

FRP(Fiver Glass Reinforced Plastic)에 대한 많은 연구가 진행중에 있다. 그러나, 대부분 전단강화 효과의 메커니즘에 초점을 맞추고 있을 뿐 앵커리지의 거동과 설계에 초점을 맞추고 있는 연구는 많지 않다. 본 논문에서는 외부 부착된 FRP 철근 콘크리트에서, FRP U-wrap의 모서리 폭에 대한 연구를 통해 U-wrap의 거동에 미치는 영향을 확인하였다.

The purpose of this research is to evaluate the mechanical characteristics of lathe scrap reinforced cementitious composites. For this purpose, the cementitious composites containing lathe scrap were made for 2mm width and 40mm length of lathe scrap, and then the mechanical characteristics such as compressive strength, splitting tensile strength, flexural strength, and elastic modulus of the cementitious composites were estimated. It was observed from the test results that splitting tensile strength and flexural strength of the cementitious composites were significantly improved than plain mortar but compressive strength and elastic modulus were only a slightly increased.

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.

When the concrete is subjected to impact of the projectile, compressive stress wave is transmitted to the rear side. When the compressive stress wave reached the rear side, is was reflected as a tensile wave. And, when the tensile stress in the concrete matrix exceeded the dynamic tensile strength, crack in the concrete was occurred.

In this research, We investigate evaluation on properties of mortars incorporated with waste LCD glass. LCD glass was grinded at 2,500, 3,500, 4,500 cm2/g blaine to replace 20% wt of cement. The compressive strength and Alkali-silica reaction test was carried out to verify effect of finess of LCD glass.

The purpose of this study is to evaluate elastic modulus of limestone concrete. As a result, elastic modulus of concrete using limestone powder was 10~20% lower than elastic modulus of concrete using OPC.

This study was intended to estimate the effect of adding stone dust sludge into concrete strength characteristics. it was found that the partial replacement of fine aggregate with stone dust sludge had an positive effect on the strength of concrete.

In this study, the heat insulating performance increase the indoor temperature of the building is applied to the concrete was compared with plain concrete. As a result, the indoor surface at the outside temperature of 10.4 ~ 22.4 ℃ temperature conditions showed a difference of up to 0.6 ℃, the lowest 0.6 ℃, indoor temperature is up to 0.2 ℃, 0.2 ℃ lower results showed a minimum.

The ceiling finishes and concrete structure, rather than problems with the performance of the acrylic panel to crack and leak, and poor adhesion between the acrylic panels has occurred. This is a cause that is generated based on different designs and structures, such as construction and finishing materials mainframe sealing materials, construction, coordination of the three principles of design appeared to be urgently necessary.

In this study, viscosity was minimized for production of viscosity-agent type high fluidity concrete with normal strength, and segregation resistance was maximized with viscosity agent and use of superplasticizer. Their applicability and physical property were examined.