Development of self sensing cement composites for structural health monitoring applications

Abstract

Material degradations, environmental conditions, natural and man made hazards, etc. highly influence the performance and lifespan of the structure. Monitoring the health of concrete structures is now required to save lives and implement appropriate repair strategies at an earlier stage of damage, thereby preventing structural collapse. In the past, strain gauges, fiber optic sensors, piezoceramic sensors, and shape memory alloys were utilized in the structural health monitoring (SHM) process. The use of these sensors in structural components is restricted due to their incompatibility, reduced sensitivity, limited area coverage, a greater number of sensor requirements, and poor durability. Consequently, self-sensing cement composite (SSC) in any form, including cement paste, cement mortar, and cement concrete, with high compressive strength, conductivity, piezoresistivity, sensitivity, and repeatability is developed to overcome the shortcomings of conventional sensors in SHM. SSC made from cementitious composites with electrically conductive elements have many applications in SHM. This research aims to develop a self-sensing composite using Steel Fibers (SF), Graphite Powder (GP), Carbon Fiber (CF), and Activated Charcoal (AC). The study also investigates the impact of Silica fume (SiF) in increasing the electro mechanical properties of cement composites. The SiF is partially replaced in the composite by 10% wt. of cement. In this research, excluding conventional composite, SSC with a total of 10mix IDs with integrated SF are cast. There are 5mix IDs having SF alone incorporated (0.25 % SF, 0.5 % SF, 0.75 % SF, 1 % SF and 1.25 % SF volume of binder) and 5mix IDs includes both SF and 10 % SiF incorporated (0.25 % SF_SiF, 0.5 % SF_SiF, 0.75 % SF_SiF, 1 % SF_SiF and 1.25 % SF_SiF volume of binder) newline