| Summary: | 碩士 === 國立海洋大學 === 河海工程學系 === 91 === Abstract
In this study, we aimed at the effects of various repair materials on the pre-cracked reinforced concrete beams with different sizes of pre-cracks. The mechanical property, physical property and electrochemical property were investigated. Experiments included repairing rate of electrochemical deposition method, permeability, flowability, tensile test, shear strength, bending strength and electrochemical tests.
Results showed that the electrochemical deposition method yielded deposition in the concrete surface as well as cracks such that the concrete surface became denser. The bending strength for repaired RC beams using this method was higher than un-repaired ones. In the injection methods, the epoxy has a better mechanical property and higher flowability than the alkali-activated slag paste (AASP). The epoxy injection method can heal crack, it also can reduce the permeability near the crack. The epoxy injection method can also enhance the bending strength of cracked beams. However, it cannot recover the bending strength of cracked beams to un-cracked one. The AASP injection method using L/Sg ratio of 0.64 had a best flowability. Since infra-red light was used to cure AASP, the consequent drying shrinkage was more apparent such that the repairing results was not good enough as expected. Nevertheless, all these three methods can improve performance of cracked beams. The accelerated corrosion test indicated that existence of pre-cracks resulted in a higher probability of corrosion. Repaired beams had a higher bending strength than un-repaired ones when they all were subjected to the same corrosive condition.
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