Utilization of Polymers as Repair Materials for Damaged Concrete Structures

一般来说，混凝土结构具有较长的使用寿命。但近年来，混凝土结构出现了早期劣化现象，其原因主要有设计和施工不当、使用劣质材料、超载、环境恶劣等，特别是碱骨料反应引起的劣化现象，在T.V.在日本，碱骨料反应几乎不可能发生，因此，有关碱骨料反应损伤混凝土结构的修复报道很少。本研究通过应用聚合物（裂缝注入、混凝土浸渍、表面衬里）修复受损混凝土结构的方法及其效果进行了试验。本研究的主要结论是：<i>采用环氧树脂灌注修补的方法，可以使受损钢筋混凝土梁恢复到与正常梁相当的静、动力性能。<ii>采用高延伸率聚合物或玻璃纤维增强聚合物，可以提高聚合物衬砌的裂缝桥接能力，并且在两种类型的载荷（弯曲和剪切）下没有观察到这种能力的任何显著差异，<iii>）与普通水泥混凝土相比，树脂混凝土在冲击载荷下具有极高的耐磨性，并且<iv>）通过应用聚合物在混凝土中获得较低的水含量对于防止由于碱骨料反应引起的膨胀是非常有效的。

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.