Prediction of Concrete Compressive Strength Using Ultrasonic Pulse Velocity: Experimental Evaluation of Direct and Surface Wave Methods

Abstract

Reliable evaluation of in-situ concrete compressive strength remains a major challenge in civil engineering practice, particularly where destructive testing is impractical or may compromise structural integrity. Non-destructive testing (NDT) techniques, especially ultrasonic pulse velocity (UPV), have been widely investigated as indirect methods for assessing concrete quality and mechanical performance [1,2]. This study experimentally evaluates the use of UPV for predicting concrete compressive strength, with emphasis on comparing direct ultrasonic pulse velocity (DUPV) and surface ultrasonic pulse velocity (SUPV) measurement techniques. Sixty standard concrete cube specimens (150 × 150 × 150 mm) were produced using multiple mix proportions at a constant water–cement ratio of 0.6 and cured for 7, 14, 21, and 28 days. UPV measurements were obtained using a portable ultrasonic tester and correlated with compressive strength results from standard compression testing. Linear and exponential regression models were developed and statistically validated using correlation analysis and analysis of variance. The results show a strong relationship between ultrasonic pulse velocity and compressive strength, with surface ultrasonic measurements providing superior predictive accuracy. The optimal linear model, C = 11.48S - 18.43, achieved a correlation coefficient of 0.83. The study confirms that surface UPV offers a practical and reliable approach for non-destructive estimation of concrete compressive strength.