Improving the non-destructive evaluation of in-situ concrete strength: The role of core location selection
Bouchra Kouddane, Youssef Jamil
Abstract. Assessing the strength of concrete in existing structures usually relies on a combination of non-destructive testing (NDT) and core-based destructive tests. This mixed strategy limits damage to the structure but still raises an important question for engineers: how can the measured in-situ strengths be considered statistically reliable? In this work, attention is directed to one crucial component of any investigation programme, namely the way in which core locations are selected. Several alternative sampling plans for core extraction are investigated, including conditional sampling, similarity-based sampling, proportional stratified sampling and a variance-oriented strategy. Their performance is analysed and compared with that of conventional random coring by means of an extensive statistical study. The methodology is applied to a large-scale case study on an existing building, where Rebound Hammer (RH) measurements and Ultrasonic Pulse Velocity (UPV) readings are collected and combined with core tests on structural members. The analysis focuses on two indicators of interest: the mean compressive strength and the associated variability. Two identification frameworks are considered: a bi-objective formulation when a single NDT method is used, and a multi-objective formulation when RH and UPV are jointly exploited. The various sampling plans are evaluated in terms of accuracy, efficiency and reliability, and systematically benchmarked against random coring. On this basis, the study identifies the strategies that yield the most robust estimates of in-situ concrete strength and proposes practical guidance to assist engineers in designing efficient and reliable investigation programmes for existing structures.
Keywords
Core Sampling Strategies, Random Coring, In-Situ Concrete Strength, Concrete Strength Variability, Rebound Hammer Testing, Ultrasonic Pulse Velocity (UPV), Combined NDT Methods
Published online 1/10/2026, 7 pages
Copyright © 2026 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Bouchra Kouddane, Youssef Jamil, Improving the non-destructive evaluation of in-situ concrete strength: The role of core location selection, Materials Research Proceedings, Vol. 58, pp 92-98, 2026
DOI: https://doi.org/10.21741/9781644903933-13
The article was published as article 13 of the book Emerging Research in Materials for Environment, and Civil Infrastructure
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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