Health monitoring of C60 smart concrete based on self-sensing

Abstract

Smart concrete is a composite material that has several advantageous characteristics such as electrical conductivity and electromagnetic shielding. It has broad application prospects in road snow and ice melting, electrical equipment grounding, structural health monitoring, and electromagnetic shielding. Thus, it is of great significance to investigate the uniaxial compressive strength (UCS) and self-sensing properties of smart concrete. In this study, two complementary properties of carbon and steel fibers were used to create functional fiber concrete. The abilities of material factors, test methods, and environmental factors to test the self-sensing capacity of concrete were investigated. Investigation of smart concrete in elastic range under stress resistivity. The results revealed that an appropriate amount of carbon and steel fibers in concrete can increase the UCS and improve self-sensing. The stress-resistivity self-sensing ability of the 0.2% carbon fiber + 0.45% steel fiber smart concrete was found to be the best. As the diameter range of the coarse aggregates increased, the self-sensing ability of the stress resistivity also increased. The environment and the measurement methods had some influence these results. When the measurement voltage was less than 5 V, the smaller the measurement voltage, the better was the self-sensing of the concrete. Concrete with a low moisture content was found to be more sensitive to stress–resistivity changes, whereas concrete with a high moisture content was more sensitive to resistivity changes under large stresses. The effect of loading speed on the self-sensing performance was relatively small. There was a good correspondence between the stress and resistivity self-sensing under cyclic unloading conditions. The resistivity decreased with an increasing load and increased with unloading, and the stability was good. The preferred carbon-steel fiber admixture for compressive-damage self-sensing concrete considering the UCS and stress-resistivity self-sensing capability was 0.2% carbon fiber+ 0.45% steel fiber. Smart concrete can be used as a stress, strain, or moisture sensor, or a load-bearing element.