Health monitoring of silica fume based concrete structures

Structural Health Monitoring (SHM) technique is employed for health assessment and characterization of materials of various infrastructural systems. The EMI technique used in SHM relies on the electromechanical coupling between a piezoelectric sensor and the structure. The strength of concrete based structures is the core concern throughout the globe. The application of supplementary cementitious material, viz., silica fume in the concrete matrix, can be a potential solution to enhance the strength of concrete structures through hydraulic and pozzolanic activity. Thus, the monitoring of strength developed in concrete systems due to the incorporation of silica fume using destructive and a non-destructive technique becomes significant. This research is primarily motivated by the health monitoring of silica fume-based concrete structures using destructive and non-destructive techniques. The concrete cube specimens were cast with the incorporation of silica fume with the replacement of cement by 0%, 5%, and 10%, respectively. Initially, the non-destructive tests viz., ultrasonic pulse velocity meter and rebound hammer, were conducted to the cubes after the 7, 14, and 28 days of curing. Further, compressive test (destructive) was performed with the cubes to determine their compressive strength after 7, 14 and 28 days respectively using compression testing machine. Furthermore, the assessed properties of silica fume-based concrete cubes have been considered for the numerical evaluation using a finite element-based ANSYS environment. For the numerical evaluations, the concrete cubes and the PZT sensors were modeled. The EMI technique is applied to extract the conductance and susceptance signatures for the modeled concrete cubes at 7, 14, and 28 days of properties consideration. The statistical indices viz. Root Mean Square Deviation (RMSD) and Mean Absolute Percentage Deviation (MAPD) were considered for the quantification of developed strength using the extracted conductance data on different days. The results showed that the quality of silica fume-based concrete is excellent and has higher surface hardness as compared to normal concrete. The compressive strength of silica fume was enhanced by 4.39% and 14.29% at 5% after 28 days of curing, respectively. Further, the extracted signatures showed shifting towards the right side, indicating more strength than normal concrete. The calculated values of RMSD and MAPD increased each day, indicating higher strength of silica fume-based concrete. The research is useful for introduction of new concept for monitoring of real-life structural systems.