Utilization of Polymers as Repair Materials for Damaged Concrete Structures

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Generally, concrete structures have long service life. But, recently, concrete structures deteriorated in early stage have been found. The causes of deterioration are wrong design and construction, use of materials of poor quality, overloading, extra severe environments and so on. Especially, the deterioration due to alkali aggregate reaction is reported in T.V.. It was said that there were almost no posibilities that alkali aggregate reaction occurred in Japan, and therefore there is few available reports about repair of concrete structures damaged by alkali aggregate reaction.Reparing methods of damaged concrete structures by application of polymers (injection into cracks, impregnation into concrete, surface lining) and their effects were tested in this study.The main conclusions obtained from this study are that <i> ) the damaged reinforced concrete beams could regain the excellent static and dynamic behaviors comparable to those of normal beams when repaired by means of injection and patching with epoxy resin, <ii> ) the crack bridging ability of polymer lining could be improved by use of polymer having high tensile elongation or polymer reinforced with glass fibers, and any significant difference of this ability was not observed under two types of loading (flexure and shear), <iii> ) the resin concrete had an extremely high abraision resistance under impact loading in comparison with ordinary cement concrete, and <iv> ) the attainment of lower water content in concrete by application of polymers was very effective for preventing the expansion due to alkali aggregate reaction.