• Journal of the Regional Association of Architectural Institute of Korea
• /
• v.20 no.6
• /
• pp.55-61
• /
• 2018

This study improved the water repair materials of the polyacrylic system applied to concrete structures by controlling expansion, strengthening water resistance, and improving cohesiveness. The improved polyacrylate repair materials were evaluated against the existing products to verify their performance and level of improvement, and applied on-site to the concrete structures that are leaking the improved water. The verification method measured the presence of water leaks and the moisture content of concrete inside. Moisture levels were measured for two months before and after material installation, and at least 0.8 - 1.7% of humidity was reduced after installing polyacrylic resin, and no leakage was found.

• International Journal of High-Rise Buildings
• /
• v.10 no.4
• /
• pp.323-334
• /
• 2021

Concrete structures may rarely collapse in fire incidents but fire induced damage to structural members is inevitable as a result of material degradation and thermal expansion. This requires certain repairing measures to be applied to restore the performance of post-fire members. A brief review on investigation of post-fire damage of concrete material and concrete structural members is presented in this paper, followed by a review of post-fire repair research regarding various types of repairing techniques (FRP, steel plate, and concrete section enlargement) and different type of structural members including columns, beams, and slabs. Particularly, the fire scenarios adopted in these studies leading to damage are categorized as three levels according to the duration of gas-phase temperature above 600℃ (t₆₀₀). The repair effectiveness in terms of recovered performance of concrete structural members compared to the initial undamaged performance has been summarized and compared regarding the repairing techniques and fire intensity levels. The complied results have shown that recovering the ultimate strength is achievable but the stiffness recovery is difficult. Moreover, the current fire loading scenarios adopted in the post-fire repair research are mostly idealized as constant heating rates or standard fire curves, which may have produced unrealistic fire damage patterns and the associated repairing techniques may be not practical. For future studies, the realistic fire impact and the system-level structural damage investigation are necessary.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.10a
• /
• pp.659-664
• /
• 1997

RC structures can deteriorate for many defective factors. In the repair and retrofit works of concrete, epoxy resins are widely used as repair materials. The object of this study is to investigate the material properties and durabilities of epoxy resins which are commonly used in repairing concrete. The material properties such as line-expansion modulus, viscosity, microstructure and physical parameter as well as the durabilities such as gravity change, tensile strength, elongation change were carried out.

• Magazine of the Korea Concrete Institute
• /
• v.7 no.6
• /
• pp.4-4
• /
• 1995

• Magazine of the Korea Concrete Institute
• /
• v.18 no.4 s.93
• /
• pp.73-79
• /
• 2006

• Magazine of the Korea Concrete Institute
• /
• v.12 no.6
• /
• pp.97-108
• /
• 2000

• Magazine of the Korea Concrete Institute
• /
• v.12 no.3
• /
• pp.70-77
• /
• 2000

• International Journal of Concrete Structures and Materials
• /
• v.2 no.1
• /
• pp.3-8
• /
• 2008

Polymer-cement composites are known repair materials. The aim of this work is to investigate the influence of various amount of dispersion of carboxylated styrene-butadience copolymer on the selected mechanical properties of polymer-cement concrete (PCC) and on its adhesion to ordinary concrete. The compressive, flexural and tensile strengths as well as frost resistance and fracture resistance of the composites are tested. Adhesion strength of PCC to ordinary concrete, as one of most important performance of good repair material is evaluated and analyzed using three test methods. The results obtained in standard pull-off test are compared with the two other tests. The first one, which is an adaptation of WST (wedge splitting test) characterizes crack propagation in the plane of bond created during repair. In the second test the resistance to shear is a measure of adhesion strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.785-792
• /
• 2000

Repair and retrofit system of concrete structures has been developed from conventional reinforced concrete overlaying, steel plate bonding and recently to fiber composite systems. Research and study on carbon, aramid, and glass fiber composite system has been actively carried out from all over the world Glass fiber composite is proved to be competitive technically and enconomically, among fiber composite system. CAF system is a system developed locally using all domestic materal, glass fabric and epoxy, and improved in shear bonding property by utilizing silica fume mixed with epoxy. All the tests on material properties, structural behavior, constructiveness at site and quality control procedure proved to be most appropriate system so far developed. Futher research work is and will be under progress for utilization of this system which will be applied to more adverse situation.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.11a
• /
• pp.154-159
• /
• 1999

In this paper we present tile results of an experimental investigation on the physical and mechanical properties of carbon fiber grid, polymer mortar, and carbon fiber grid reinforced plain concrete flexural members. In order to repairing and reinforcing damaged and/or deteriorated existing concrete structural members, new materials have been developed and utilized in the construction industries. But the physical and mechanical behaviors of the material are not well understood. To use the material effectively various aspects of the material must be throughly investigated analytically as well as experimentally. In this investigation we found the physical and mechanical properties of carbon fiber grid and polymer mortar which are directly utilized in the repair and reinforcement design of damaged or deteriorated concrete structures. In addition, we also investigate the strengthening effect of carbon fiber grid on the plain concrete flexural test specimens. It was found that the material can be used to repair and strengthen the concrete structures effectively.