Research On The Self-sensing Characteristics And Application Of Smart Polymer Concrete

After a large-scale infrastructure construction in our country,a large number of existing structures are in urgent need of effective structural reinforcement and long-term structural health monitoring.Smart Polymer Concrete(hereinafter referred to as SPC),that is,a kind of new smart material curing with polymer such as epoxy resin as cementitious material,sand as aggregate and the external admixture with certain functional properties.The new smart materials not only exert their good bonding and durability properties,but also have features such as self-sensing,self-healing,self-diagnosis and self-adaptation.When it is developed and applied to the actual project,the new smart polymer concrete will not only strengthen and repair the existing structures,but also play the role of structural health monitoring.According to the actual engineering requirements,this paper summarizes the current status of existing smart polymer concrete at home and abroad.Based on it,a new type of smart polymer concrete material is developed and its self-sensing characteristics under compressive and tensile load are studied.Then the material is applied to the concrete beam components to form the concrete self-monitoring system.The main contents and innovations are as follows:(1)The preparation method and procedure of SPC block in our group are optimized.Mechanical stirring process and water bath heating method are adopted,and the surface modification of graphite is improved by coupling agent.By adopting wet mixing method of external admixture,more stable results are obtained.(2)By the preparation of SPC compression block,the pressure-sensitive properties are studied.On the basis of graphite powder,steel bead and steel slag were respectively incorporated to study the influence of different conducting admixtures on the pressure-sensitive properties of SPC block.The data were processed and the curves were analyzed.The pressure-sensitive properties of SPC blocks with diphasic graphite and steel bead,diphasic graphite and steel slag were analyzed respectively.(3)The tensile properties of SPC were studied by preparing SPC tensile specimens.The tensile curves of SPC specimens with different content of steel bead under tensile load were studied.The mechanical properties of SPC specimens were analyzed.The theoretical model of the pull-sensitive property of SPC is established.(4)The SPC sensing material is placed in the compression zone and the tension zone of the experimental beam.Measure the change of resistance of the SPC material in the compression zone and the tension zone during loading.The results show that during the compression process of the concrete beam,the SPC resistance increases with the increase of strain,which indicates that the SPC material can effectively monitor the concrete beam.This paper is a preliminary exploration for SPC sensing material in the future of the actual project.