Measurement of core bond strength in reinforced concrete column using magneto rheological fluid assisted Ultrasonic measuring technique

The present work deals with the investigation of core compressive strength in reinforced concrete column with the slip angle orientation and bond stress relationship using Magneto rheological fluid (MR fluid)-based non-destructive testing principle. Ultrasonic method is used to obtain the crack width and slip angle orientation of the rebar. In addition to that, the bond strength can be determined through the rheological disturbance in the MR fluid medium. Experiments to determine the axial compression behaviour of cylindrical concrete specimens were carried out by placing the MR fluid discs at three distinct zones. Ultrasonic waves were generated and scattered over the MR fluid disc based on two different angles of propagation (90ᴼ and 45ᴼ). The results demonstrated that the percentage of variation in the measured rebar strain for M30/RRD 1.0 is found to be 25.75% of the values measured for M30/RRD 0.5. The maximum bond strength is found to be 24.63 MPa for M30/RRD 1.5 with slip orientation angle of 14ᴼ. Moreover, the minimum difference in the observed values of ultrasound pulse velocity was −0.78 m/s for M20/RRD 1.0 with the magnetic field strength of 40 mT.