Field Analysis of Schmidt Hammer Test Results in Assessing the Compressive Strength of In-Situ Concrete Structures with Emphasis on Hot and Humid Climatic Conditions: A Case Study of Projects in Behbahan and Gachsaran

Mirzaie Aliabadi, Mahbobeh; Shahidzadeh, Mohammad Sadegh; Nayebi, Reza

doi:10.22059/ceij.2026.396721.2326

Field Analysis of Schmidt Hammer Test Results in Assessing the Compressive Strength of In-Situ Concrete Structures with Emphasis on Hot and Humid Climatic Conditions: A Case Study of Projects in Behbahan and Gachsaran

Articles in Press

Authors

¹ Assistant Professor, Department of Civil Engineering, Faculty of Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, iran

² Master's student in civil-structural engineering, Department of Civil Engineering, Faculty of Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, iran

10.22059/ceij.2026.396721.2326

Abstract

This study evaluates the field reliability of the Schmidt rebound hammer for estimating in-situ concrete compressive strength, specifically addressing challenges posed by hot and humid climatic conditions in Behbahan and Gachsaran, Iran. Field campaigns followed ASTM C805 on five structures using a novel, disciplined protocol designed to mitigate procedural and environmental bias. This involved mandatory mechanical surface preparation, employing a ten-point sampling grid, and integrating rigorous statistical processing, notably Interquartile Range (IQR)-based outlier identification. Results confirmed significant spatial variability in rebound numbers across structural elements, strongly influenced by construction practices and environmental exposure, particularly high temperatures. For instance, a C30 foundation yielded estimated strengths near its lower design limit (27.9–34.8 Mpa). The findings emphasize that uncalibrated, generic correlations are insufficient and can yield misleading estimates in these regions. The paper concludes that the diagnostic value of the Schmidt hammer can be substantially increased through mandatory region-focused improvements, including the development of site-specific calibration curves, routine use of complementary core testing for validation, and strict logging of environmental parameters. This combined approach improves the interpretability and practical reliability of NDT in challenging environments.

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