Sensing characteristics of waterborne epoxy resin based graphene sensor to concrete strain

To promote the application of conductive nanocomposites in concrete deformation monitoring， the waterborne epoxy resin based graphene sensor was prepared by solution blending method. Firstly， the influence of graphene mass fraction on the sensitivity， linearity， repeatability and fatigue resistance of the sensor was studied. Then， the key factors affecting the strain sensing characteristics of the sensor on concrete was analyzed. Through concrete compression tests， the resistance response of the sensors to concrete strain under monotonic and cyclic compression was studied， and the relationship between the resistance change rate of the sensor and concrete compressive strain was established. The results showed that， when the graphene mass fraction was between 0.4% ~ 0.8%， the sensor had a high sensitivity coefficient， good linearity and repeatability. When the graphene mass fraction was 0.6%， the fatigue resistance of the sensor was optimal. The Poisson's ratio of concrete had a significant impact on the strain sensing sensitivity coefficient of the sensor. The sensitivity coefficient decreased as the Poisson's ratio increased. The sensor could effectively sense the strain of concrete under cyclic loads， exhibiting good repeatability and stability， and could be used for fatigue monitoring of concrete structures.