• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.4
• /
• pp.482-488
• /
• 2022

In this study, the durability of ultra rapid hardening mortar for sewage pipe was evaluated by type of mortar binder. As a result of analyzing the internal structure for each type of mortar, it was confirmed that Al₂(OH)₃ was generated in the internal structure of the CAC-based mortar, and its corrosion resistance was superior to that of other types of mortar. As a result of the compressive strength test, OPC had the tsmallest strength, followed by CAC100 > CAC100P > CAC80. This trend was similar to the previous study results. Chloride ion penetration resistance and freeze-thaw test showed similar trends. That is, CAC and C12A7 were better than OPC, and CSA was worse than OPC. This is mostly beacuse of cracks caused by expansion of CSA-based mortar. CAC100P mix showed the best chemical resistance. It is thought that this is because the alumina gel formed inside the mortar and the polymer combine to make the internal structure more dense.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.3
• /
• pp.259-265
• /
• 2014

This study is to analyze durability of water-repellent paints mixed with water-repellents as outer surface finishing materials, and evaluate its feasibility. General functions and water-repelling effects were tested, and the feasibility was evaluated based on the test results. The experimental results of heat conduction durability, air permeability, absorption, and bond strength suggested that water-repellent paints mixed with water-repellents were suitable for finishing materials. Considering overall general durability performances, stable mixing ratios were 2, 5, and 8%.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.6
• /
• pp.145-152
• /
• 2013

As a typical construction material, concrete has been used in building all kinds of structures since the late $19^{th}$ century. Although it was recognized to secure durability as long as the regulations on design and construction have been reasonably complied, the trends of life-shortening and deterioration have frequently occurred due to all kinds of the external effects that have been experienced during the procedures of using the structures. To make matters even worse, deterioration of the concrete structures according to deterioration can not be controlled any more. Finally, the reality is that repair and maintenance are necessary in the maintenance aspect of the concrete structure. In this study, CRM(Chemical Resistance of Laminating Reinforcement Method), which had been developed to reinforce the surface of concrete and specially improve chemical resistance performance, has been applied to enhance the existing repairing and maintenance method. Therefore, the result has been drawn with comparison and analysis of the specimens applied with the general repairing and maintenance method and CRM through a variety of durability test in this study. With the result of the test, durability of the specimen applied with CRM has been more improved than the existing repairing and maintenance method, which is judged as because of the laminating effect due to reinforcement of epoxy impregnated of alkali-resistance fiber and double layered fiber reinforced seat.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.3
• /
• pp.133-142
• /
• 2014

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF Slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. In this study, We've got the plan to assure the chemical stability of EAF Slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF Slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF Slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of the Korea Institute of Building Construction
• /
• v.13 no.3
• /
• pp.235-241
• /
• 2013

In this study, a mortar was produced using re-dispersible polymer powders that addresses the defects of aqueous polymer and improves the durability of cement mortar. Also, an attempt was made to examine the properties of polymer modified mortars using re-dispersible polymer powders by strength and durability tests between ordinary Portland cement mortars and polymer modified mortars mixed with aqueous dispersion. The test showed that strength and durability are improved considerably compared with ordinary Portland cement mortar, and the performance of aqueous polymer cement mortar was considerably improved. Accordingly, it is expected that high-quality prepackaged polymer modified mortars can be produced using re-dispersible polymer powders.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.12
• /
• pp.1296-1303
• /
• 2012

There is a certain limit to reproduce phenomena between the real vehicle and road, since the existing methods to verify durability of the wheel are mostly uni-axial tests. And the change of durability of the wheel can't be predicted since these tests don't consider the camber angle and lateral force as important factors. In this paper, the FE models of the wheel-tire and drum are created. Then, the vertical and lateral loads are applied to wheel-tire assembly and the camber angle is applied by inclining the wheel-tire assembly to the drum. Based on the analysis result, the crack position is predicted to be created in the body of the wheel. The variation of the stress according to the camber angle is verified and the maximum spot of the stress changes continually.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.943-948
• /
• 2013

In this study, the characteristics of polymer-modified mortar which include UM resin, eco-friendly resin, was studied for improving the durability of concrete. UM and cement mortar were mixed with a certain percentage. Eco-friendly UM resin polymer-modified mortar was evaluated by compressive strength, splitting tensile strength, flexural strength, water absorption and chemical resistance experiments. The characteristics of eco-friendly UM resin polymer-modified mortar were evaluated by experiments. Performance of compressive strength and splitting tensile strength were decreasing. On the other hand, performance of flexural strength, water absorption and chemical resistance were increasing. Eco-friendly UM resin polymer-modified mortar reinforced concrete durability performance is excellent.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.3
• /
• pp.201-208
• /
• 2014

A Pt catalyst ($Pt/G_xC_y$) supported on the hybrid supporting materials composed of graphene oxide (GO) and carbon black (C) was fabricated using polyol method to improve the durability of electrocatalysts. The electrochemical performances measured by cyclic voltammograms using three-electrode system revealed that the properly designed $Pt/G_xC_y$ catalyst exhibited higher durability than that of Pt/C catalyst without sacrificing an electrocatalytic acivity. In the oxygen reduction reaction (ORR) performed in acid solution with the rotating disk electrode, the $Pt/G_xC_y$ catalyst showed greater mass and area-specific activity than those of Pt/C catalyst.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.523-524
• /
• 2009

This study focused on possibility of new optimized durability design for deteriorated RC structure's repairing. New optimized durability design adopted Life Cycle Assessment as sustainability index.

• Magazine of the Korea Concrete Institute
• /
• v.14 no.3
• /
• pp.71-76
• /
• 2002

콘크리트는 거의 반영구적인 재료라고 인식되어져 왔으나, 최근들어 해양환경, 적설한랭지대, 도심과 같은 열악한 환경속에서 예상보다 빨리 조기열화 되는 현상이 널리 알려지면서 콘크리트 구조물의 구조적 성능뿐만 아니라, 장기적인 내구성에 대한 관심이 높아져 가고 있다. 실제로 여러 선진국에서 염해와 같은 열화환경의 피해를 받은 콘크리트 구조물이 예상공용년수 이전에 철거되거나. 개보수 비용이 초기 건설비용보다 더 많이 드는 예가 적지 않게 보고되면서, 적절한 내구성 유지대책 및 구조물의 장수명화를 위해 많은 연구와 노력이 진행되고 있다.(중략)