New And Old Concrete Interfacial Bonding Materials And Strength

The bond between new and old concretes or mortars in actual project is affected by many factors. Interface is the weakest region in new-to-old concretes or mortars. Usually, the interfacial bond strength is very low, and approach to the strength of substrate. There are many kinds of bond materials and methods of dealing with the interface, however. The effect varies remarkably and can't meet the ideal demand.As to the problem above, explore to the interfacial bond and factors of various bond materials on the basis of a great deal of tests. Many experimental researches have been done and given preliminary discuss on the bond and mechanism. Meanwhile, proper bond materials and better proportion are offered, under the background of the difference interfacial bond methods and curing systems.This paper also makes a compare on the bond effect of various bond materials and given reference for the project application and the future research of bond mechanics and endurance.The research work can be divided into two parts:1. Research on the interfacial bond of new-to-old mortars.This paper has research on the bond performance under the conditions of different curing systems, bond method aging and proportion, by means of "8" mould and giving preliminary discuss on the mechanism of different materials by use of SEM.The paper adopts such materials as common cement materials, mineral modified cement-based materials, polymer modified cement-based materials and epoxy resin and places emphasis on the polymer modified cement-based materials. Polymers include NP powder, SBR latex, acrylic acid latex, pure acrylic acid latex, chlorobutyl latex and epoxy latex.2. Research on the bond of the new-to-old concretes.By means of the test of spitting bond between new and old concretes, the bond performance of different bond material is researched.The bond effect of various bond material is also researched by use of the test ofpored-drilled drawing bond between new and old concretes. This paper also makes a contrast with the effect of mortars' bond, which offers a meaningful reference on how to choose bond materials and to appraise the bond effect.