• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.57-60
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• 2003

Generally, normal concrete has the disadvantages of low tensile strength, low ductility and volume instability. To improve its performance, fiber reinforced cimentitious composite(FRCC) have been development. These composites are composed of cement, sand, water, a small amount of admixtures, and an optimal amount of fiber like synthetic fiber and steel fiber. This research investigates influence of sand, hybrid fiber and fiber volume fraction, and reports the test results of mechanical properties, fracture behavior and failure pattern of the FRCC. Our experiment was observed that sand mixed FRCC has lower compressive strength and higher bending strength than no sand mixed FRCC, and more steel fiber mixed FRCC has higher compressive strength and bending strength. Hybrid FRCC of steel and polypropylene had superior properties than FRCC of polypropylene only in same fiber volume fraction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.59-62
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• 2007

Nowadays, polymer-cement mortars are widely used in construction field(floorings and pavements, water-proofings, adhesives, repair materials, deck coverings, anti-corrosive linings) Because of excellent performance such as high tensile and flexural strength, waterproofness, excellent adhesion, good durability, improved wear and chemical resistances. This article presents the results of experimental study that investigates the effect of ambient temperature on the strength properties of polymer-modified cement mortar. Results show that when increasing the polymer proportion in mortar on different ambient temperature, the compressive strength and flexural strength are decreased, and also alkali resistance is decreased.

• Journal of the Korea Institute of Building Construction
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• v.13 no.1
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• pp.1-9
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• 2013

There has recently been a great deal of research into the appropriate building materials for eco-friendly construction. In the field of earth architecture, there have been walls made of pure earth or with rammed earth including a small amount of cement. The purpose of the study is to investigate the possibility increasing compressive strength through a more eco-friendly composition by using Hwangtoh binder rather than cement to increase the strength performance of rammed earth. It was found that the more the ratio of binder was increased, the more the strength was increased, but enhancement did not increase noticeably in the lower part that did not compact completely, and proper height to pour earth is 200 mm. When stone dust was added, compressive strength was lower than when adding fine aggregate and coarse aggregate, but a finer surface texture was provided.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.89-90
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• 2018

The strength of cement mortar is one of the most important factors in design and construction. Strength can vary widely depending on factors such as water cement ratio, aggregate and materials and curing. In the study, it was found that the standardized method of making the cement mrtar was different from the standard method of preparing the cement mortar by the different process of the cement mortar. I wanted to know the difference. Experiments were carried out to investigate the differences in strength, physical properies and performance depending on the points when the sample were made long in vertical form.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.706-711
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• 1998

Structural tests of the PSC Beam bridge using high strength concrete, concrete compressive strength 700kg/$\textrm{cm}^2$, are conducted for the application including durability and serviceability of the bridge. Current design safety factors with respect to the jacking force and the service design load DB-24 are applied to the design of the bridge. Concrete compressive strength 700kg/$\textrm{cm}^2$, girder depth 2.3m, girder space 3.2m, span length 20m, and slab thickness 27cm are selected for the bridge test. The Bulb-Tee section of the girders is applied instead of I section because it is well known more stable to the longer span(40m). Static load test(4 beams) with composite and non-composite section, and fatigue load test(1 beams) with composite section are conducted. Crack moment, ultimate load, deflections with load steps, and strains of the beam section for those bridges are investigated. The structural test results of the bridges showed a good performance for a safety and a serviceability.

• Journal of Korean Association for Spatial Structures
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• v.18 no.3
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• pp.117-124
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• 2018

In the post-tensioned concrete member, additional reinforcement is required to prevent failure in the anchorage zone. In this study, the details of reinforcement suitable for the anchorage zone of the post-tensioned concrete member using circular anchorage was proposed based on the experimental results. The tests were conducted with the compressive strength of concrete and reinforcement types as variables. The experimental results indicated that the additional reinforcement for the anchorage zone is required when the compressive strength of concrete is less than 17.5 MPa. U-shaped reinforcement shows most effective performance in terms of maximum strength and cracks patterns.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.564-569
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• 2009

Due to the uneasy controllable qualities of the substructures such as pile and foundation, which are laid on underground, geotechnical engineers have applied conservative criteria to them. Therefore, the specification criterion of cast-in-situ concrete pile, which allows only one fourth of the compressive strength of structural capacity, has forced geotechnical designers to consider the most uneconomical design regardless of satisfying the grade of quality-control, required performance, construction cost and so on. Thus, in this study, we proposed the less conservative criteria on the strength of concrete pile, based on the experimental testing results of cast-in-situ concrete piles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.15-18
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• 2007

The purpose of this study is to suggest a reference for an extensive evaluation about effectiveness of four types of fibers to control plastic shrinkage crack of concrete. So in this study for the practical use in construction field, the plastic shrinkage cracks shown from four types of concrete reinforced by mixing four types of fibers are quantitatively evaluated in points of the workability and compressive strength. Test showed that the mixing of Cl, N, P fibers except for C2 fibers decreased fluidity of fresh concrete. Compressive strengths of four types specimens were similar. Plastic shrinkage cracks were reduced by mixing each fiber, especially C2 fibers was very effective to prevent the plastic shrinkage crack. Therefore the reinforced concrete mixed with C2 fibers exhibited superior mechanical performance than the others.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.99-100
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• 2019

Water repellent and waterproofing agents fail to act work properly if cracks or detachment occurs outside. The method of making mortar was tested by classifying it into two methods: direct water-repellent put in concrete and water-repellent spray to sand method. It was found that the compressive strength was decreased as the amount of water repellent was increased. As a result of measuring the contact angle, all of the specimens were hydrophobic. The spray method showed greater water repellent effect than the direct mixing method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.162-163
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• 2015

A borosilicate glass was powdered to incorporation into the cement for the purpose of improving the neutron shielding performance of concrete. The particle size of the borosilicate glass powder was prepared by a similar to that of cement. 50×50×50mm size of cube specimens were measured a compressive strength. As a result, compressive strength of 10% borosilicate glass powder replaced specimens were improved than that of plain specimens.