Real-time monitoring of structures under extreme loading using smart composite-based embeddable sensors
Rajani Kant Rao, Bellam Sukumar Sindu, Saptarshi Sasmal
Abstract
Cementitious composites reinforced with conductive nanoparticles, also known as smart composite-based sensors, are emerging as novel sensors for real-time monitoring of structures. The present study deals with the development of embeddable smart composite-based sensor (called as e SCS), for monitoring the damage evolution in large-scale beam-column (B-C) sub-assemblages. Firstly, a systematic approach has been developed to fabricate the sensors through incorporation of functionalized (-COOH) multi-walled carbon nanotubes (MWCNTs). The optimum dosage of CNTs required for developing sensors with maximum conductivity and piezo-resistivity was ascertained by determining the percolation threshold limit. The best performing e SCS was then successfully embedded at the critical locations of full-scale B-C joint specimens. The embedded sensors are used, for the first time, for damage monitoring of the B-C sub-assemblages subjected to reverse cyclic loadings. From the study, it is found that e SCS with 0.50 wt.% COOH-MWCNT shows excellent piezoresistive behaviour and gauge factors are found to be approximately 730, 457 and 396 for the applied compressive stress ranges of 2–4, 2–6 and 2–8 MPa, respectively. The embedded sensors showed the excellent strain sensing capability under reverse cyclic loading. The present study demonstrates the suitability of embedded e SCS sensors for robust structural health monitoring applications.