산업부산물인 폐유황의 재황용을 목적으로 개질처리된 유황을 대상으로 콘크리트용 혼화재료로써의 물성검토를 위하여 개질처리된 유황을 콘크리트에 외할 첨가하여 개질유황 첨가별 압축강도 및 내구성능을 평가한 결과를 고찰하였다.

The purpose of this study is to estimate basic mechanical properties of steel fiber reinforced Alkali-Activated Slag(AAS) concrete. Principle variable is the fiber volume fraction: 0, 0.5, 1%. Two type cement composites were used: Steel Fiber Reinforced Concrete(SFRC) and AAS. Mechanical properties of AAS concrete and SFRC, including compressive strength, elastic modulus, flexural strength, splitting tension.

This study was carried out to evaluate effects of curing method and age on compressive behavior of steel fiber reinforced Alkali-Activated Slag(AAS) concrete. AAS and Steel Fiber Reinforced Concrete (SFRC) material with specific compressive strength of 30MPa was reinforced with 0% to 1% steel fibers at the volume fraction. Two types of curing methods were used: water curing and exposed curing. Curing time is 3, 7, 28 day. Experimental results indicated that compressive strength, elastic modulus, compression index.

Fundamental approach to compute gas and water permeability of concrete is suggested. For several compositions of cement pastes, the permeability coefficients were calculated with the analytical formulation, followed by a microstructure-based model. As the result of calculation of permeabilities for concrete, hydration leaded to the significant reduction of the coefficients. Meanwhile, the relationship between gas permeability and water permeability has a linear function for cement paste based on Klinkenberg effect, however, which is not effective for concrete.

Chloride adsorption is very ambiguous in the mechanisms of deterioration of concrete exposed to marine environment. Author suggested that chloride adsorption with cement hydrates depends on pH value of pore solution. However, adsorbed chloride ions can be dissolved in concrete under the combined deterioration environment of carbonation and chloride penetration. In the condition, the most crucial issue is the amount of dissolved chloride ions in cement paste due to carbonation. In this study, dynamics experiment was designed to quantify the effect of CaCO3 on chloride adsorption. Based on the experiment results, the final goal of this study is to develop integrated system for predicting chloride adsorption /desorption behaviors.

In this study, application of industrial by-products as an ultra rapid hardening cement substitute for semi-rigid pavement grout was evaluated. The examination of abrasion resistance showed that the loss ratio was 8.0~11.5% in every mixing condition, which indicates a good abrasion resistance.

For insulation to concrete, lightweight aggregate and the hollow microspheres were mixing to improve the insulation performance. Hollow microspheres according to the replacement method and the replacement ratio was to compare the degree of performance improvement.

This study is the basic experiment for manufacturing non-cement matrix of lightweight based on blast furnace slag. Consequently, the decrease ratio of the density of matrix about the density of mix showed Ca(OH)2 up to be the highest when adding 2.5%. And the compressive strength increased as the addition ratio of Ca(OH)2 was increased.

This research was performed to improve the bond strength of polymer concrete in the longspan bridge. Specimens were designed to 3 types; steel deck, steel deck attached dump and welding. In conclusion, Welding and dump type is higher than steel deck. Also, steel deck attached dump or welding to be arranged by 160mm is more effective than the others.

The purpose of this study is to use organisms or micro-organism functions for eco-friendly water-purification according to concentration in porous concrete using EM, utilizing bioremediation.

Recently, field applications and researches for concrete using by-products, fly-ash, GGBS, etc, have been conducted. In case of GGBS, however, quality control and replacement amount is limited because of some disadvantages. In this study, high early strength concrete using GGBS was evaluated applicability for concrete structural material. In order to evaluate, compressive strength and shrinkage test were conducted.

In This study to estimate the early-age strength of concrete, the electro-mechanical impedance method was utilized. The electro-mechanical impedance varies with the mechanical properties of host structures. Because the strength development is most influential factor among the change of mechanical properties at early-age of curing, it is possible to estimate the strength of concrete by analyzing the change of E/M impedance.

This paper discusses on the durability of developed high-performance shotcrete for Bobsleigh track construction in 2018 Pyongchang winter Olympic Game, concentrating on strength development, rapid chloride permeability, surface scaling, freeze-thaw resistance, and dry shrinkage

This research investigated the influence of adding SRA(Shrinkage reducing agent) on the direct tensile behavior of UHPFRC(Ultra high performance fiber reinforced concrete). The experimental test results revealed that the post cracking strength and strain capacity for the cement hydrated cement paste without at SRA were higher than that incorporate with 1% SRA.

The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. but a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research structural insulation concrete what improved insulation performance using micro form admixture and lightweight aggregate.

Since electrical resistivity of concrete can be measured in a more rapid and simple way than chloride diffusivity, it should be primarily regular quality control of the electrical resistivity of concrete which provides the basis for indirect of quality control of chloride diffusivity during concrete construction. This study can provide a non-destructive approach for durability design of marine concrete and it is expected that the result is subsequently used as a calibration curve for an indirect control of the chloride diffusivity based on regular measurements of the electrical resistivity during concrete construction.

Traditionally main driving force of chloride penetration in concrete have been regarded as diffusion, however, 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. 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. When the life length for such a concrete structure on a large sea water depth is estimated using the normally used models, the concrete test specimen.

In this study is experiment result of steel fiber reinforced concrete panel with damage characteristics. To assess the damage characteristics of SFRC panel, aggregate size and steel fiber was used as a variables. The experimental results show that steel fiber reinforced concrete panel is superior compared to normal reinforced concrete panel on area loss rate and weight loss rate. The experimental results of concrete panel with aggregate size 8mm is superior than 20mm.

The effects of maximum aggregate size on mechanical properties of high-strength steel fiber reinforced concrete (SFRC) were investigated in this work. Test main variable is maximum aggregate size (8 and 20mm). The cylinder specimens was casted for compressive test and the prism specimens was tested under four points loading. Test results indicated that the addition of steel fiber improves compressive and flexural behavior of high-strength concrete. Also smaller aggregate size improve mechanical properties of high fiber volume fraction SFRC.

This experimental study investigates the influence on the flexural behavior of strain-hardening cement composite (SHCC) with HR and SWP Shrinkage Reducing Admixture (SRA). SRA can also improve flexural strengths and flexural toughness.