Performance Investigation of Rebound Hammer Testing within a Non-Destructive Testing System for Structural Concrete Evaluation

Abstract

This study uses the Schmidt Rebound Hammer method to evaluate precast concrete components of the Annex Building at IIT Madras in a non-destructive manner. In order to ascertain the concrete’s structural sufficiency and compliance to the designated design grade, the examination attempts to evaluate the concrete’s in-situ quality, surface hardness, and indicative compressive strength. To assess the consistency and general state of the concrete components, rebound measurements were methodically documented and examined. The study emphasizes the value of rebound hammer testing as an effective and trustworthy method for the initial evaluation of existing reinforced concrete structures.

Introduction

Non-destructive testing (NDT) is a vital technique in the construction industry for evaluating the quality, strength, and integrity of materials and structures without causing damage. It helps detect defects, cracks, voids, and weaknesses in concrete, steel, and other building components, ensuring safety, compliance with standards, and the longevity of structures. NDT is cost-effective, time-saving, and critical for maintenance planning, structural evaluation, and monitoring older buildings.

Among NDT methods, the Schmidt Rebound Hammer test is commonly used to assess the surface hardness and indirect compressive strength of concrete. The test relies on the rebound of a spring-loaded plunger, where higher rebound values indicate stronger concrete. It is simple, quick, and economical, suitable for walls, beams, slabs, and columns. Proper preparation of the concrete surface, correct handling of the hammer, and multiple readings are essential for reliable results. Rebound numbers are converted into estimated compressive strength using manufacturer charts or standards. Concrete quality is classified based on rebound values: very good (>40), good (30–40), fair (20–30), and poor (<20).

This study applied the rebound hammer test to evaluate the walls of the Annex Building at IIT Madras. Experimental results showed that both Wall W1 and Wall W2 had very good hard layers, confirming high surface strength and satisfactory concrete quality. The study highlights the effectiveness of the Schmidt Rebound Hammer as a reliable NDT method for in-situ assessment of precast concrete structures.

Conclusion

The analysis of the Schmidt Rebound Hammer test results for the precast elements in the Annex Building at IIT Madras indicates that the average rebound value corresponds to an estimated surface compressive strength of approximately 46 Mpa. This value aligns well with the expected performance for M50 grade concrete used in the structure. Overall, the test results confirm that the in-situ concrete quality remains within the acceptable range, demonstrating adequate strength, uniformity, and satisfactory performance of the structural elements.

References

[1] Bureau of Indian Standards. (1991). IS 13311 (Part 2): Non-destructive Testing of Concrete – Rebound Hammer Method. New Delhi: BIS. [2] Bureau of Indian Standards. (2000). IS 456: Plain and Reinforced Concrete – Code of Practice. New Delhi: BIS. [3] Bureau of Indian Standards. (1959). IS 1199: Methods of Sampling and Analysis of Concrete. New Delhi: BIS. [4] Bureau of Indian Standards. (2018). IS 516 (Part 1/Sec 1): Methods of Test for Strength of Concrete – Compressive Strength. New Delhi: BIS. [5] Neville, A. M. (2011). Properties of Concrete (5th ed.). Pearson Education. [6] Gambhir, M. L. (2013). Concrete Technology (5th ed.). McGraw Hill Education. [7] Google Images. (n.d.). Schmidt Rebound Hammer. Retrieved from https://images.app.goo.gl/PA22zXyc4es7jMC5A [8] Google Images. (n.d.).Conversion based on the compressive strength and the rebound number. Retrieved from https://images.app.goo.gl/Qmmm196F5riY1FjTA

Copyright

Copyright © 2025 Dr. Atika Ingole , Tejswini Gollawar . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.