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Nigerian Journal of Technology

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A Comparative Analysis of the Rebound Hammer and Ultrasonic Pulse Velocity in Testing Concrete

JC Agunwamba, T Adagba

Abstract


This work presents a study on the comparison between some non-destructive testing tech-niques (Rebound Hammer and Ultrasonic Pulse Velocity). Tests were performed to com-pare the accuracy between the rebound hammer and the ultrasonic pulse velocity methodin estimating the strength of concrete. Eighty samples (cubes of 150 x 150 x 150) wereprepared using two mix designs of 1:2:4 and 1:3:6 with a constant w=c ratio of 0.45 andwere tested at 7, 14, 21 and 28 days. The slump test was between 62 - 78mm. The resultsobtained from the non-destructive testing methods were correlated with the compressivestrength results which showed that a higher correlation existed between the Rebound Ham-mer and the compressive strength than the Ultrasonic Pulse Velocity. The rebound ham-mer readings had a correlation coecient of 0.794 while the ultrasonic pulse velocity hada correlation coecient of 0.790 for the 1:2:4 mix and the rebound hammer readings for1:3:6 was 0.783 and that for the ultrasonic pulse velocity was 0.777. Statistical analysisof the results obtained showed that there was no signicant dierence between the meansof the two methods for both mix at a 0.05 level of signicance.



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