Research About The Bond Technology Of The New And Old Concrete

The durability of the concrete construction has been an important issue in the engineering field with the growth of use of construction. Under the influence of natural environment and working load, the concrete constructions have to be maintained and reinforced continuously. Therefore, there is a broad market for maintaining and reinforcing concrete construction. The bonding quality of new to old concrete has a direct effect in the quality of the construction. Therefore, the bonding quality of the new to old concrete has been a hot topic in the contracture industry at home and abroad. But the theory has till been being searched to get perfected and accepted. A huge actual constructions and tests has proved that the bonding power of the bonding surface is often too small to satisfy the actual stress, and that in the construction of the new to old concrete, the construction process is blind because there are no unified standards of the construction technology, which leads to the quality of the construction is inferior. And in the design process, the designers who can't identify the strength of the bonding surface can not make an accurate, economic and proper design, which will lead to waste or engineering accident. Based on these, CSCEC instituted the project'reinforce and mend of the construction', the project is given to research and science institute design of CSCEC in Guizhou. Scientific research and design institute of CSCEC in Guizhou cooperate with Prof. Peng Xiaoqin, and research the bond technology of the new and old concrete. Which are researched to four points as follows:1. Several major methods evaluating the degree of roughness were analyzed, and their advantages and disadvantages were analyzed. A simple and easy handling method was put forward and concluded the relation between it and the sand cone method.2. Several processing methods to concrete surfaces were analyzed, and their advantages and disadvantages were analyze Through experiment, the relationship of the water-jet stress and the degree of roughness and the bond strength of the old concrete surface was researched when treating the surface of the old concrete with spraying high-press water.3. The influences of several factors including the strength of the concrete, the kind of interface agent, mending orientation and the quantity of containing water in the old concrete on bond strength of the new and old concrete was studied, and the optimum parameter to each factor was obtained, which guides the actual construction in some...