Guide to non-destructive concrete strength assessment: Homogeneity tests and sampling plans. (15th May 2022)

• Record Type: Journal Article
• Authors: Saleh, Eman; Tarawneh, Ahmad; Dwairi, Hazim; AlHamaydeh, Mohammad
• Is Part Of: Journal of building engineering. Volume 49(2022)
• Publication Date: 2022-05-15
• Subjects: Concrete strength -- Assessment of existing buildings -- NDT -- Core tests -- Sampling plan; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2022.104047
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: Non-Destructive testing (NDT) of concrete can be used in conjunction with destructive techniques (e.g., coring) for an efficient assessment of concrete strength in existing structures. A major drawback that hinders the efficient use of test measurements is the limited description specified by the relevant standards regarding how the overall investigation program should be carried out. This study discusses two elements of the investigation program: homogeneity of different concrete zones and the locations for core extraction. Different homogeneity measures have been investigated to identify heterogeneous concrete zones using extensive statistical analysis of synthetic datasets. The considered homogeneity measures were: t -test, Kolmogorov-Smirnov (KS) test, earth mover's distance, and Cramér-von Mises distance. The results of the analysis indicated that the earth mover's distance and Cramér-von Mises distance outperform the traditional t -test in the identification of heterogenous concrete zones, and hence, recommended to be used for concrete assessment. Furthermore, different sampling plans of core locations, namely, similarity sampling, cluster sampling, proportional stratified sampling, and post-sampling are investigated through the generation of risk curves as indicators of the estimation quality of each sampling plan. It was found that a reduction in the probability of inaccurate concrete strength estimation is feasible. As such, the utilization of sampling plans in concrete assessment can enhance the reliability of the assessment. Highlights: Innovative methods for the evaluation of the homogeneity of concrete zones are presented. Homogeneity detection is essential to make a valid inference from the non-destructive test results. Moreover, different sampling plans of core locations are proposed. These sampling plans allow improving the reliability of concrete strength assessment.