| With the rapid development of economic construction of our country,construction industry has gradually turned to a new period in which building andrepairing are both very important. The maintenance and reinforcement for the existconcrete structure have become an important research subject in construction project.Further each functional parameter got mostly experts’ attention. Not only thestrength of repairing concrete but also the durability of repairing concrete aresignificant index which can be used to judge qualified concrete. Generally, corrosionof concrete reinforcing bars is the main cause of structure destruction, which can bemostly caused by the chloride ion erosion. Based on this, chloride ion penetrationresistance of concrete is considered as an important index to judge the durability ofconcrete. In the paper, the chloride ion penetration experiments of original concreteand repairing concrete are carried out, further the influence of repairing state on theconcrete strength and the chloride ion permeability are analyzed.The experiment study in this paper is supported by maintenance project of thetechnology houses of Public security bureau in Maanshan city by in Anhui branch ofHebei Construction Group Company. The concrete specimens of three kinds ofstrength grade (C30C40C50) are used to cross patch, further the compressivestrength and Cl-penetration resistance ability of repairing concrete are studied.Based on the experiment results, the effect of repairing states on the concrete areanalyzed. Two types concrete specimens are used in the testing. One is the concretecube specimen of100100100mm3, which is used to measure the compressivestrength. Another is the concrete cylinder specimen ofφ10050mm3, which is usedto measure the Cl-penetration ability. Meanwhile, the standard testing method ofconcrete durability---the RCM was applied to Chloride penetration testing, throughwhich chloride-ion diffusion coefficient of concrete was determined. In theexperiment, the direction of grouting is required parallel to bonding surface ofrepairing concrete specimen. At the same time, it is assumed that the compressivesurface and Cl-penetration direction are all parallel to bonding surface. Based onprevious traditional chloride ion penetration model, the modified Cl-penetrationmodel is put forward which is suitable for repairing concrete. Further the concept of "ratio of strength and permeability" is put forward in order to judge the optimal crossrepairing concrete combination, which can guide effectively the maintenance projectof existing damaged concrete structure.It can be concluded that slightly higher strength concrete should be used torepair for the low strength concrete (C30) under the condition of repairing concretemeeting the strength requirement. While it is not reasonable to use a greatly differentstrength concrete to repair. At the same time a slightly different strength concreteshould be used to repair for the high strength concrete (C40). |
