Study On Bonding Interface Properties Of Mortar Repaired By Ordinary Silicate And Sulphoaluminate Cement System

Cement concrete is the most widely used man-made material in modern engineering.Most of the important large-scale buildings,transportation,water conservancy,port and other projects are built by cement concrete.For more than one hundred years,some cement and concrete materials will be damaged due to material defects,cracking,carbonization,steel corrosion,and the decrease of frost resistance.The repair of damaged concrete structure,not only greatly reduce the waste of funds,but also does not affect the normal use of buildings,so in the building materials industry,the research and application of concrete material repair technology has gradually been paid attention to.The repairing system consists of three phases:repairing material,original base material and transition zone between them.The transition zone between them is very important.Repairing mortar bond interface has played an important role in the tensile bond strength of concrete repair system.In this paper,the mix ratio of ordinary Portland cement repair mortar and Portland-sulphoaluminate cementitious material system repair mortar has been studied.By comparing the content of cementitious materials,the dosage of admixture,and the different dosage of water reducing agent,the influence of cementitious materials on the performance of ordinary repair mortar was studied.This paper studies the influence of different wetting degree of base on the bonding performance of repair mortar system,and the influence of different interface agents and repair mortar construction time on the bonding performance of repair mortar system,and explores the best construction scheme.The results indicate that:The results show that the optimum content of cementitious material is 30%35%,mineral admixture is 5%,expansion agent is 8%,rubber powder is 0.8-1.0%,cellulose ether is 0.02-0.05%,water retaining thickener is 0.02-0.05%,polycarboxylate water reducer is 0.03%.When the ratio of sulphoaluminate to Portland cement is 5:1,the setting time,strength and original strength of rapid repair mortar meet the performance index of general rapid repair mortar.In this paper,by comparing the tensile bond strength of the repair system when the base is in natural state,dry state and saturated state,it is determined that the worst tensile bond strength is in the dry state.The base course is more suitable for saturated water treatment when the liquid interface agent is used in the repair project.When the interfacial agent is in the semi dry state,the tensile bond strength of the repair system is better.In this paper,different types of interfacial agents on the mortar interface micro analysis,to observe and analyze the interface structure of the entire interface agent.The experimental results were verified.