Experimental Study On Mechanical Properties And Fracture Property Of Self-repairing Concrete

Self-repairing concrete material is seen as an important part of intelligent structure, which can solve some technical gist issues that are difficult to Solve or can not be solved by conventional measures. There is great application potential to make sure of the safety and long-term durability of some valueable civil infrastructural facilities such as high-rise,bridge,nuclear power station,etc, and to relieve many wreck factors such as typhoon,seismic impact,etc. In this paper, The experimental researches on glass capsules matched mechanical properties of self-compacting concrete are carried out with the orthogonal experiments;Different type of adhesives are selected as the repair adhesive,then the experimental researches on fracture property of self-repairing concrete are carried out with three-point bending tests. The main achievements are summarized in detail as follow:.Firstly, based on the requirements of self-repairing concrete and considered the existent material, the ideal single-composing idiosyncrasy adhesives RTV silicone adhesive polyester adhesive and polyvinylacetate adhesive are selected as the repair adhesive.Secondly, the orthogonal experiments are made to analyze the effects of geometry parameter and mingled volume of capsules on mechanical properties of concrete, and the optimal combination of geometry parameter and mingled volume of glass capsules is selected.Thirdly, Steel fiber reinforced self-repairing concrete is selected as the basal material.then the experimental researches on fracture property of self-repairing concrete with three-point bending tests are carried out. The load displacement (P δ) curves and load^crack mouth opening displacement (p CMOD )curves are obtained. The comparison of the maximum load p_max , fracture parameters (precritical crack propagation length â–³a_c ,critical crack tip opening displacement CTOD_c initiation fracture toughness K_ICⁱⁿⁱ and unstable fracture toughness K_IC^un and fracture energy G_f between before and after repair are made,at the same time,a comparison of fracture parametets of self-repairing concrete with those of steel fiber reinforced concrete is also made.then.after repairing of self-repairing concrete,fracture toughness and fracture energy are investigated to obtain the repair effect and repair difference of three type of adhesives.Fourthly, according to the experimental phenomena of fracture damage occurring chiefly in tacky surface of self-repairing concrete after repairing of self-repairing concrete beam, the models of adhesive interfacial fracture are proposed, in addition,views of fracture mechanics and the theory of mechanics of composites are used to evaluate fracture mechanism of self-repairing concrete.In the end, based on the experimental data, the formulas for calculation of fracture toughness and fracture energy are proposed after repairing of self-repairing concrete.and the accuracy of the formulas for calculation is verified by the experimental data.