Steel structures have been prevented from corrosion damage using by paint coating. The durability of paint coating can be changed by installed environment condition of steel structures. In this study, thus, deterioration test of paint coating was conducted for various environmental condition. Deterioration levels of paint coating specimens exposed by each artificial environment were examined from visual inspection.

In this paper, Results of mock-up test for mitigating carbonation of high volume mineral admixture concrete by spreading waste cooking oil. Concrete incorporating 60% of BS and 30% of FA with the size of 900×600×200 are discussed. Denatured Silicate paint is also applied to compare the performance. Test results indicate that the application of ERCO and DSP enhance carbonation resistance.

The objective of this paper is to provide the feasibility of premixed type ternary blended aggregates using raw fly ash(Ra), crushed sand(CS) and sea sand(SS) by studying fresh properties of the concrete. Ra is varied from 2.5% to 10% with interval of 2.5% by weight of mixed aggregates. Test results indicates that the replacement of Ra by mixed aggregates with low quality crushed sand and sea sand resulted in decrease of slump and air contents due to increased viscosity.

In this study, it evaluate the electrical conductivity of fiber reinforced cement composite by Fiber type. Hooked-ended steel fiber, Smooth steel fiber and Amorphous metallic fiber were reinforced 2.0 vol.% in cement composites respectively. The electrical conductivity was evaluated by calculating the electrical resistivity of each specimen after measuring the electrical resistance.

The study investigated the fluidity and compressive strength properties of cement paste containing Ferro-Nickel slag powder by different curing conditions to estimate the applicability of Ferro-Nickel slag powder for cement replacement materials.

NSGAⅡ algorithm was employed to optimize the multi-objective problem to find mixing proportions of 60MPa high strength self compacting concrete, which was implemented numerically on MATLAB to calculate the optimal mix proportion considering multi-objective characterizing the four performances like compressive strength, passing ability, segregation resistance and manufacturing cost depending on the factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content.

D-optimal experimental design was employed to model the effect of mixing factors on several performances of 60MPa high strength self compacting concrete and to numerically calculate the optimal mix proportion considering multi-objective characterizing the four performances like compressive strength, passing ability, segregation resistance and manufacturing cost depending on the factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content, the experiments were made at the total 32 experimental points which reduced comparing with standard experimental design.

To find economic mixing proportions of 60MPa high strength self compacting concrete optimizing a multi-objective problem was performed, which was implemented numerically on MathCAD15 to calculate the economic and optimal mix proportion considering multi-objective characterizing the five performances like compressive strength, passing ability, segregation resistance, manufacturing cost and bulk density depending on the factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content.

It was found that the firming agent was satisfied in terms of mobility for improving compactibility and filling characteristics since reviewing the basic properties of the fluidized filler according to the types of firming agent in domestic market. But, it was difficult to secure adequate strength for re-excavation.

As a result of abrasion resistance test of decoration wood-based flooring board laminated with PVC on plywood, compared to the flooring board laminated with general HPL surface decoration materials, it was available to secure far higher abrasion resistance. It seems to contribute to secure initial durability and maintenance of decoration wood-based flooring board as an important means, and it might be available for saving repair and maintenance costs due to flooring board issues.

This study was conducted improve reduction of flexural performance cuased by using acrylic round bar. For the specimen, different fiber contents(0.2%, 0.4%)was used for recycled waste ALC and the bottom ash light weight aggregate respectively to confirm the flexural performance according to the fiber content. The result of the test showed that the specimen with 0.4% fiver content shown to have improvement of flexural performance.

As a result to check basic physical characteristics of plyood and fabric board, both of them satisfied the criteria of KS F 3126 but hardened fabric board only showed changes in the absorption width expansion rate. This may imply that continuous expansion and swelling can occur if hardened fabric board is exposed to moisture for longtime, and it should be considered when selecting a product and mainteaning it.

In order to verify the strength of slurry shotcrete compared to existing shotcrete, The results were analyzed and evaluated.

In Korea, for about 2 months from late July to early September, it is expected that the average temperature will exceed 25 ℃, therefore, construction shall be conducted with hot weather concrete. In the case of the concrete placed at this time, if proper curing quality control measures are not established, problems such as plasticity, drying, shrinkage, and crack are caused. Therefore, in this study, an optimum method is proposed by mutually comparing the temperature history characteristics of the slab concrete in accordance with the change of surface coated curing material type.

The purpose of this study is to analyze the crack characteristics of concrete by comparing the previously developed transparent bubble sheet and the aluminum deposited bubble sheet whose surface is exposed by applying to the walled structure apartment actually constructed. The aluminum deposited bubble sheet was developed for the purpose of temperature reduction through heat reflection.

In this study, fundamental properties and change with time of cement mortar accompanied with change of solid content ratio of PC type superplasticizer were analyzed. As a result, it was clarified that the flow and air content decreased as the solid content ratio decreased, and the compressive strength increased slightly.

The cause of the falling of the girder of a PSCI bridge under construction was investigated to prevent from similar accidents. The I-type bridges are the most unstable phase after the girder construction and before the installation of concrete slab. Generally the bridges are taken into consideration in order to secure stability in the construction process. However, this bridge was found to have fallen in a rainy and strong wind with some neglect of the procedures and methods presented in the design.

This study introduces abnormal noise phenomenon of steel deck plate bridge which have not been mentioned in the literature or reports. The abnormal noise occurred from the time when the girder was installed and the welding was completed. And it had continued after the bridge opened. In this study, firstly, the characteristics of abnormal noise is analyzed. Also it presents the mechanism of noise generation.

The tunnel structure is a structure supported by the ground rigidity around the tunnel excavation. Therefore, when tunnel excavation occurs, various problems arise in the tunnel when the ground stiffness is weak. These characteristics should be considered because the ground conditions in the design of tunnels are often different from the construction conditions investigated during tunnel construction

The bridge coping part may cause cracking due to over-loading of superstructures. And the external prestressing method is a typical reinforcement method for a crack of coping. However, in case of design and construction error, it is difficult to expect sufficient reinforcement effect and reinforcement coping part may be damaged. For this reason, in this paper, The damage case of the coping with external prestressing method was introduced and the cause of the damage of anchorage zone was analyzed. As a result of the analysis, the cause of the damage of the anchorage zone was due to the shortage of bolt anchorage length. Also, as a result of simple calculation, the anchorage length of the bolt did not satisfy the pullout force that was occurred by the moment.