In present study, effect of micro carbon fibres on strain sensing property and structural behavior of the reinforced concrete (RC) beams in absence of stirrups was experimentally investigated. A total of three RC beams of dimensions, 125 mm width, 350 mm height and 1500 mm long were manufactured without stirrups. All the three beams had different longitudinal reinforcement ratios (0.9%, 1.43% and 1.03 %) and uniform strength of concrete of 36.5 MPa. All the beams had carbon fibre based concrete (CFBC) at top and bottom surface in mid span for a length of 350mm and depth of 78 mm. All the beams were tested to failure under four point bending test for evaluating strain sensing property and structural behavior of carbon fibre based concrete. Fractional change in resistance (FCR) was calculated for top and bottom surface of the beam and co-related with strain in concrete and strain in tensile reinforcement. It was observed that as load increases on the beam, the FCR was increasing for the bottom surface (tension side) and decreasing for the top surface (compressive side). The trend of change in FCR for top and bottom surface is observed to be similar as that of strain in tensile reinforcement and concrete. It was also observed that, obtained FCR graphs can be used for strain and damage detection in beam. All the beams failed in shear with improved load carrying capacity as reinforcement ratio increased.

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While there are distinct structural health monitoring methods available, health monitoring using smart concrete is a newly emerging technique. In this technique, cement mortar/concrete is made as self-sensing by introducing carbon fibres in the conventional concrete that can sense strains/stresses/loads. Therefore to study in detail about this technique, in the present research, concrete cubes made from self-compacting concrete of 15 cm size reinforced with carbon fibres in various dosages were cast. Different tests have been performed on sufficient specimens that include stress/strain sensing and crack/damage sensing that resulted in finding co-relation between properties of concrete cube and change fractional resistance (FCR). The obtained results promised that when carbon fibres in the specimen are dosed with 1.5% can give the best co-relation between FCR and concrete cube properties and also the same dosage found to be best suited for stress sensing and crack/damage sensing.