A New Method For Improving Micro And Fine Structure Of Interfacial Layer Of New-to-Old Concrete

The most defaults of repairing due to the failure of new-to-old bond interfacial layer. The paper improves the bonding from two aspects. One is using KH-570 silane coupling agent solution to change the surface of old concrete. The other is modified the mortar primer with shrinkage-reducing, flying ash and their admixture. The tests apply on the surfaces of the old mortar primer and granite. To efficently complete the research. This paper proposes a new method of testing the pull-off strength of new-to-old bond interfacial layer. Macroscopical results show that two methods can improve the strengths of bond interfacial layers remarkablely. STM can clearly observe the interfacial layer with less interspace and more evenness and close-grained. Using organic silicon chemistry and material knowledges we put forward a frame of reference about how the silane coupling agent effects with the new-to-old bond interfacial layer. At last ,the paper investigate the influence of many factors(such as the chroma of silane coupling agent solution, brush times, the temperature of interfacial layer, water wash, etc.). The paper explores using silane coupling agent to enhance the durable ability of the middle-stress concrete. At last, the paper put forward prospect to the further research.