This study investigates the monitoring of progressive compressive strength development in concrete using non-destructive testing (NDT) techniques, aiming to provide a reliable, in-situ alternative to traditional destructive testing. An experimental program was conducted on concrete specimens (mixes with varying strength ranges) to track strength evolution at early and mature ages, specifically 7, 28, and 90 days. The NDT techniques, primarily focusing on Ultrasonic Pulse Velocity (UPV) and the Rebound Hammer (RH) test, were utilized to estimate the compressive strength (SonReb method). The research confirms that while sole NDT methods possess inherent inaccuracies (roughly \\\15-20% for RH), combining RH and UPV significantly improves the precision of in-situ concrete strength predictions. This study presents a systematic investigation of the monitoring of progressive compressive strength of M30 Concrete using a pendulum-based non-destructive testing (NDT) technique. The research is based on the principle of the coefficient of restitution, where the rebound angle of a pendulum after impact is correlated with the compressive strength of concrete. \ strength evaluation using the Compression Testing Machine (CTM) is destructive and unsuitable for in-situ monitoring. To overcome this limitation, a pendulum-based device is used to measure rebound angle at different curing ages (2, 7, 14, 21, and 28 days). Two empirical relationships were developed 1) Y= -0. 0867x²+12. 318x-405. 74 2) Y= 0. 0028x²+0. 2613x+56. 976 where x is the rebound angle, and Y is the compressive strength (MPa). The results show a strong correlation between rebound angle and compressive strength, validating the effectiveness of the proposed method. The study demonstrates that this technique is economical, simple, and suitable for real-time field applications. \
Deshpande et al. (Thu,) studied this question.