Incorporation of Smart Concrete in Large-Scale RC Beams for Evaluating Self-Sensing and structural Properties

Abstract

Only using a small number of samples in the absence of reinforcement, the concrete self-monitoring behaviour is tested, which is inaccurate for real-world structures. The behaviour of concrete is primarily tested, which can be inaccurate for structures in real time. This study examined the self-sensing ability of large-scale reinforced concrete beams that are 1500 mm long and 125 mm wide embedded with smart concrete at top and bottom surfaces for a length of 350 mm. As shear failure is catastrophic, the present study focused on evaluating RC beams' self-sensing property failing under shear, and shear reinforcement was not given for the same reason. A total of six RC beams, 3 of are 250 mm deep and 3 are 350 mm deep with variable reinforcement ratios, were tested in a four-point bending test to study the self-sensing properties such as strain and crack/damage sensing. Mechanical/structural properties of all the beams have been documented, along with self-sensing properties. The results obtained showed that partially placed smart concrete in the RC beam's pure bending region successfully sensed all strain and damage/cracks without any impact due to beam depth and reinforcement ratio. During testing, it was observed that 250-mm-deep beams failed due to flexure/concrete crushing, and 350-mm-deep beams failed due to shear. In particular, smart concrete's self-sensing property showed promising results for the beams that failed due to flexure by representing all the cracks developed in the pure bending region. Fraction change in resistance (FCR) has also been obtained for all the beams during self-sensing testing, and this FCR has been successfully co-related with concrete strain in compression and steel strain in tension. An empirical equation was also derived separately for beams that failed in shear and flexure, which provides a co-relation between FCR and concrete or steel strain.