PSI - Issue 64

Said Debbakh et al. / Procedia Structural Integrity 64 (2024) 130–136 S. DEBBAKH and al. / Structural Integrity Procedia 00 (2024) 000 – 000

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partially-destructive (pull-off) methods in order to assess the concrete compressive strength. The non-destructive test is considered as a direct derivation where the method relies on rebound hammer index to obtain the compressive strength. The second method carried out indirect calculations of the compressive strength by converting the tensile strength to the compressive strength. Eighteen measurements were performed at each reinforced concrete column and the reliability of both tests was discussed. The main conclusions are the following:  The rebound Hammer test would not be fully reliable to assess the concrete strength. This test is influenced by many factors that affect surface hardness. For instance, moisture content, age, surface smoothness and carbonation. For this raison, the rebound Hammer test should not be an alternative test to assess the actual compressive strength of concrete.  The study showed that the manufacturer’s rebound curve largely overrated the actual compressive strength of concrete, nonetheless, as long as the rebound hammer is calibrated, it can be a reliable device for the assessment of the concrete quality.  The pull-off test seems to be more reliable to assess the tensile strength.  Pull-off test may be used for detecting zone effect of concrete.  The studied reinforced concrete columns revealed that a small number of tests on representative locations can give reliable tensile strength results, and highlighting the importance of the overall zone tests to achieve reliable results.  In structural column, the pull-off test must be performed on the three zones (upper, medium and lower) to detect the zone effect, leading to more robust decisions.  Rebound Hammer and pull-off tests operates on the same depth of concrete. Acknowledgements This work was possible with the support of the National Center of Integrated Studies and Research on Building Engineering. Special thanks to the technical stuff of the center. References Benidir Adel, Said Debbakh, and Siham Chaibeddra. 2023. “On the Assessment of Actual Compressive Strength of Concrete in Reinforced Columns : Influence of Core Diameter and Slenderness Ratio.” 18(1):1 – 15. Pucinotti, Raffaele, and Milena Tripodo. 2009. “The Fiumarella B ridge: Concrete Characterisation and Deterioration Assessment by Nondestructive Testing.” International Journal of Microstructure and Materials Properties 4(1):128 – 39. De Stefano, M., M. Tanganelli, and S. Viti. 2013. “On the Variability of Concrete Streng th as a Source of Irregularity in Elevation for Existing RC Buildings: A Case Study.” Bulletin of Earthquake Engineering 11(5):1711 – 26. Frappa, Giada, Massimiliano Miceli, and Margherita Pauletta. 2022. “Destructive and Non -Destructive Tests on Columns and Cube Specimens Made with the Same Concrete Mix.” Construction and Building Materials 349(July):128807. Karahan, Şebnem, Aydın Büyüksaraç, and Ercan Işık. 2020. “The Relationship Between Concrete Strengths Obtained by Destructive and Non Destructive Method s.” Iranian Journal of Science and Technology - Transactions of Civil Engineering 44(1):91 – 105. Nobile, Lucio. 2015. “Prediction of Concrete Compressive Strength by Combined Non - Destructive Methods.” Meccanica 50(2):411 – 17. El-Mir, Abdulkader, Samer El-Zahab, Zoubir Mehdi Sbartaï, Farah Homsi, Jacqueline Saliba, and Hilal El- Hassan. 2023. “Machine Learning Prediction of Concrete Compressive Strength Using Rebound Hammer Test.” Journal of Building Engineering 64(November 2022):105538. Kumavat, Hemraj R ., Narayan R. Chandak, and Ishwar T. Patil. 2021. “Factors Influencing the Performance of Rebound Hammer Used for Non Destructive Testing of Concrete Members: A Review.” Case Studies in Construction Materials 14:e00491. Sanchez, Kristine, and Nathaniel Tar ranza. 2015. “Reliability of Rebound Hammer Test in Concrete Compressive Strength Estimation.” International Journal of Advances in Agricultural & Environmental Engineering 1(2). Bungey, J. H., and M. N. Soutsos. 2001. “Reliability of Partially -Destructive Tests to Assess the Strength of Concrete on Site.” Construction and Building Materials 15(2 – 3):81 – 92. Kouddane, Bouchra, Zoubir Mehdi Sbartaï, Sidi Mohammed Elachachi, and Nouzha Lamdouar. 2023. “New Multi -Objective Optimization to Evaluate the Compressive Strength and Variability of Concrete by Combining Non- Destructive Techniques.” Journal of Building Engineering 77(August):107526. EN 1542, 1999: Products and systems for the protection and repair of concrete structures - Test methods - Measurement of bond strength by pull-