• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1014-1020
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• 2004

In this study, durability of the nano-level inorganic polymer based coatings which can provide a barrier against the ingress of moisture or aggressive ions to concrete is discussed. For the durability evaluation of the coatings, chloride penetration test, accelerating carbonation test, freezing and thawing test, and sulfate ponding test are conducted. As the result of this study, concrete applied nano-level inorganic polymer based coatings has a much higher resistance to the ingress of chloride ion, carbon dioxide, moisture and aggressive acid than plain concrete and epoxy resin based paint by means of crosslinking three-dimensional structure with concrete structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.217-220
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• 2004

Metakaolin is a cementitious material for producing high-strength concrete. This material is now used as substitute for silica-fume. In this paper, we did the durability test such as chloride ion diffusion, chemical attack. repeated freezing and thawing, carbonation. In the chloride ion diffusion test, according to the increase of substitute of metakaolin & silica-fume for binder, the diffusion coefficient is more reduced. And in the chemical attack test, according to the increase of substitute, the resistance is more excellent. In the other durability test, the concrete using metakaolin is also compared with those of the portland cement concrete and silica fume concrete. According to these tests, we recognized that metakaolin is able to be used as a substitute for silica-fume.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.721-726
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• 2003

The Durability of Concrete Structure is serverely degraded due to mainly carbonation, sulfate attack and chloride ion diffusion in concrete. The ultimate purpose of this study is to obtain how much the durability of Concrete Structure is improved according to the variation of physical properties in concrete or the frequency of surface coating on concrete. Where, variation of physical properties is a water-cement ratio or amount of air. The experiments are the chliride ion diffusion test, the lapid corrosion test, the lapid carbonation test, the test on resistance to freezing and thawing. Finally, this study shows that the effect by the surface coating method is better than the variation of physical properties in concrete.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.457-465
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• 2007

In this paper, polymer-modified repair materials using polymer dispersions with six repair methods are prepared with various polymer-cement ratios, and tested for compressive and flexural strengths through each curing condition such as dry cure, water cure, and freezing and thawing cyclic action. And, the adhesive interface between the polymer-modified mortar and mortar substrate is observed by a scanning electron microscope. From the test results, the compressive and flexural strengths of cement mortar repaired by polymer-modified mortar are improved with a rise in the polymer-cement ratio regardless of the type of polymer and curing conditions. Such an improvement in the strengths of polymer-modified repair materials to ordinary cement mortar is explained by the high adhesion of polymer-modified mortar. Strength reduction of polymer-modified repair materials after freezing and thawing cyclic actions is recognized, but it is lower than that of unmodified mortar. Especially, cement mortar repaired by polymer-modified mortar with a St/BA emulsion has good strength properties compared with those of SBR latex and PA emulsion. Accordingly, it is judged that polymer-modified mortars with a St/BA emulsion are possible to use as repair materials to ordinary cement mortar and concrete.

• Journal of Conservation Science
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• v.34 no.3
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• pp.143-155
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• 2018

In this study, we investigated the properties and manufacturing methods of soil mural finishing layers fabricated using animal glue, starch adhesive(wheat paste), and Dobak glue. We assessed the workability and weatherproofing properties of the earthen plaster and finishing layers fabricated using concentrations of 3%, 5%, 7% and 10% for each adhesive. The results showed that a mixture using 3% or 5% starch adhesive or 3% Dobak glue was suitable for constructing the finishing layer. For finishing layers made with animal glue, earthen plaster had poor workability. It was dry and easily broken as the concentrations of animal glue increased. However, specimens made with low concentrations of animal glue did not exhibit surface deterioration after a freezing-thawing test. Therefore, animal glue mixtures could possibly be used for constructing finishing layers in concentrations lower than 3%. Mixtures containing starch adhesive produced plasters with good workability. Additionally, starch adhesive enhanced compression strength. However, when starch adhesive was mixed at concentrations above 7%, the surface exhibited roughening and staining in freezing-thawing tests. When Dobak glue was used in mixtures, it enhanced compression strength, but concentrations above 5% produced specimens with surface cracking. For concentrations of 3%, there were no cracks and the specimens were stable after freezing-thawing tests, so concentrations below 3% of Dobak glue are suitable for constructing finishing layers. We expect this study will be useful for restoring the traditional technology of soil mural finishing layers and suggest using adhesives to construct the finishing layer.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.333-338
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• 2000

At present, reinforced concrete pipe has been widely used as drain pipe. However, many reinforced concrete pipe is exposed at deteriorated environment by the growth of a sulfur-oxidizing bacterium isolated from corroded concrete. The purpose of this study is to evaluate the effects of lining by polymer-modified mortar on the development in durability of reinforced concrete pipe. Polymer-modified mortars ate prepared with various polymer typer as cement modifier and polymer-cement ratio and rested for compressive and flexural strengths, adhesion in tension, acid resistance test, freezing and thawing test, and lining test of product in the field. From the rest results, it is apparent that polymer-modified mortars have good mechanical properties and durability as lining material. In practice, all polymers can be used as lining materials for reinforced concrete pip, and type of polymer, and polymer-cement ratio and curing conditions are controlled for good lining product.

• Corrosion Science and Technology
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• v.15 no.1
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• pp.28-37
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• 2016

Due to the increased construction of offshore concrete structures and the use of de-icing salts for the purpose of snow removal, the needs for the development of anti-corrosive concrete are increasing. To solve these problems, an evaluation of the mechanical and durability properties for concrete were conducted by mixing modified-sulfur as 0 %, 5 %, 10 %, 15 % cement weight ratio. Both strengths and the properties affecting durability such as water absorption coefficient, chloride ion permeability, accelerated carbonation resistance, rapid freezing and thawing, and chemical resistance were evaluated. All evaluations performed were according to the test specifications associated KS. The results indicate that mixing of modified-sulfur lowed chloride ion permeability and improved chemical resistance.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.569-574
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• 2002

Generally, the limestone powder is known to have some advantages in rheology of fresh concrete, resistance of material separation, and enhancement of strength at early ages. Recently, great attention is being paid to limestone blended cements in the manufacture of concrete, especially in the countries of Europe. The purpose of the present study is to establish the mechanical and durable properties of concrete containing slag and limestone powder. In this paper, the chloride ion penetration test, rapid carbonation test and rapid freezing-thawing test is carried out to study durability of concrete with various content of limestone powder. Futhermore, the strength of concrete is evaluated with various ages.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.27-34
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• 2005

The purpose of this study is to improve the durability performance of polymer modified cement composites for repair of concrete under combined aging conditions. The experimental procedure was divided into three parts. First, the replacement level of mineral admixtures in polymer modified cement composites were determined in an experimental study based on a Box Behnken design. Second, the flow value, compressive strength and chloride permeability test of sixteen types of mixtures were conducted. Test results show that the polymer modified cement composites were effected on the improvement of the compressive strength and permeability performance. Third, the effects on the replacement level of silica fume mixture was evaluated by the compressive strength, chloride permeability, chemical resistance and repeated freezing and thawing cycles test. They demonstrated that the polymer modified cement composites using mixture of silica fume, fly ash, and blast furnace slag improved the durability performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.761-764
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• 2006

Nowadays, It is openly reported that concrete structures have been attacted by freez and thaw. However, it is not clearly defined how to understand & measure the test method of freez and thaw of concrete structures. Thus, in this strudy, We performed the research with the test results using provision of ASTM C672 of freez and thaw durability of concrete. Also, it is identified suitable test method to measure of freez and thaw.