Experimental Research On Two-sided Shearing Bonding Property Of Fiber Cement Mortar To Concrete

The reinforced concrete structure, which plays an indispensible role in the process of the construction of nearly most the modern buildings, has become the most widely used structure in the world today. However, with the rapid growth of population, the problems such as the densely located buil dings and the unreasonable planned buildings occur, which causes the even sharper contradiction between architecture and environment. Therefore, one of the alternative ways to realize the social sustainable development is to reinforce and renovate the existing buildings. The way of reinforcement by using the fiber cement mortar layer has become the main method with its high bond property and low cost. In the process of applying the fiber cement mortar layer to reinforcing the cement structures, that whether the experiment can achieve the desired effect mainly depends on the interfacial bond property between the fiber cement mortar and the cement structures that will be reinforced on condition that the strength of the fiber cement mortar be ideal, which can meet the experiment demands. This thesis explores the interfacial bond property of the fiber cement mortar-concrete structures by applying the method of two-sided shearing experiments and the main research contents and results are as follow:(1)It is set 9 mortar strength grades which ranges from M20 to M100 in the two-sided shearing experiments and each strength grade includes three types of fiber cement mortar(polyvinyl alcohol fiber,polypropylene fiber and steel fiber). Each of the 27 experimental groups is set 3 bond structures. And it is through the 81 concrete structures that the research explores the interfacial bond property between the fiber cement mortar and the concrete.(2) By using a jack to take the two-sided shearing experiments of concrete species covered by fiber cement mortar, this thesis aimed to investigate the influence of fiber types, strength of concrete and strength of fiber cement mortar on the bonding property between concrete and fiber cement mortar. The results of the experiments demonstrated that the shear strength between concrete and polyvinyl alcohol fiber cement mortar was the highest, that of polypropylene fiber took second place, and the shear strength between concrete and steel fiber was the lowest. It was concluded that the higher the compression strength of concrete or compression strength of fiber cement mortar was, the higher the shear strength was.(3) By using the Analysis of Variance to analyze the influence of the types of the fiber, the concrete strength and the fiber cement mortar strength on the shear strength, it is found that the types of the fiber have significant influence on the shear strength. The concrete strength and the fiber cement mortar strength have more significant influence on the on the shear strength. The interaction between the types of the fiber and the concrete strength, the interaction between the types of fiber and the fiber cement mortar has little influence on the shear strength.(4)By Building the 5-9-1 BP neural network prediction model, it is found that the calculated value of the shear strength agrees well with its predicted values, and the prediction accuracy can satisfy the need of engineering application. Namely, it is feasible to apply the BP neural network shear strength prediction model to predicting the shear strength whose prediction results can provide a theoretical guide for the practical reinforcement engineering.