Experimental Study On Self-repairing Capsules Working Mechanism Of Concrete Beam Bridge

For a long time,the problem of repairing the concrete cracks is seen as an important topic in research in the academic field and engineering field. It is often believed that, there are two kinds of cracks in concrete structures:Microscopic cracks that cannot be seen by eyes and macroscopic cracks that can be seen by eyes. All the macroscopic cracks developed from microscopic cracks. This paper mainly studies the self-repairing of the microscopic crack.According to the properties,characteristics and usages of concrete crack adhesive,by using the urea and the formaldehyde (or the urea resin added with melamine) as wall materials and the epoxy resin of bisphenol type A as core material, through the method of in situ polymerization, the microcapsule of epoxy resin can be produced,which is wrapped by the uranium. Through the tests of the test pieces of common concrete, concrete with microcapsule inside, fiber concrete with microcapsule inside, we can find out the effluence of microcapsule towards the strength of the test piece of concrete and the result of self-repairing of the microcapsule. The main researching conclusions are as follows:①On the basis of consulting and analyzing enormous overseas and domestic documents, we came up with the self-repairing mechanism of microcapsules on concrete cracks,and synthesized microcapsule in the laboratory;②The built-in microcapsule of 7%～10% could enhance the strength of the fiber concrete,but could not be clear of the microcapsule effect on the strength of ordinary concrete;③Testing the flexural ratio and crushing ratio of the test piece. The fiber concrete with microcapsule of 7%～10% had the flexural ratio improved and the crushing ratio reduced. It was evident that the microcapsule has improved the flexibility of fiber concrete. Therefore,microcapsule exerted repairing effluence on the fiber concrete.④Testing the permeability of the test piece. By adding fiber in ordinary concrete, we could reduce the height of water penetration by 24.4 percent; by adding 7% microcapsules in fiber concrete could reduce the height of water penetration by 11.8 percent; by adding 10% microcapsules in fiber concrete can reduce the height of water penetration by 26.5 percent. Therefore,the microcapsule could help to repair the fiber concrete.