Criteria for identifying concrete homogeneous areas for the estimation of in-situ strength in RC buildings

Masi, Angelo; Chiauzzi, Leonardo; Manfredi, Vincenzo

doi:10.1016/j.conbuildmat.2016.06.017

Cited by 37 publications

(16 citation statements)

References 13 publications

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“…For normal strength concrete, some in situ core tests were carried out [18,19]. However, such tests are rare for high strength concrete members.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Compressive Strength of High Strength Concrete Using Non-Destructive Technique and Concrete Core Strength

Park

2017

Applied Sciences

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Abstract:Estimating the compressive strength of high strength concrete (HSC) is an essential investigation for the maintenance of nuclear power plant (NPP) structures. This study intends to evaluate the compressive strength of HSC using two approaches: non-destructive tests and concrete core strength. For non-destructive tests, samples of HSC were mixed to a specified design strength of 40, 60 and 100 MPa. Based on a dual regression relation between ultrasonic pulse velocity (UPV) and rebound hammer (RH) measurements, an estimation expression is developed. In comparison to previously published estimation equations, the equation proposed in this study shows the highest accuracy and the lowest root mean square error (RMSE). For the estimation of compressive strength using concrete core specimens, three different concrete core diameters were examined: 30, 50, and 100 mm. Based on 61 measured compressive strengths of core specimens, a simple strength correction factor is investigated. The compressive strength of a concrete core specimen decreases as the core diameter reduces. Such a relation is associated with the internal damage of concrete cores and the degree of coarse aggregate within the core diameter from the extracting process of the cores. The strength estimation expressions was formulated using the non-destructive technique and the core strength estimation can be updated with further test results and utilized for the maintenance of NPP.

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“…For normal strength concrete, some in situ core tests were carried out [18,19]. However, such tests are rare for high strength concrete members.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Compressive Strength of High Strength Concrete Using Non-Destructive Technique and Concrete Core Strength

Park

2017

Applied Sciences

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“…In this very active field for research, one can also consider some recent interesting ideas which have emerged these recent years, like: the analysis of various scales of heterogeneity in an existing building [10], which can take benefit of a dense mapping of the structure with NDT measurements, the added value than can be derived from conditional coring, which corresponds to define the location of concrete cores on the basis of prior NDT results, instead of following a preconceived sampling scheme ( [11][12]), changing the conversion model identification techniques for better addressing the concrete variability [13].…”

Section: Rilem Tc 249-isc Agendamentioning

confidence: 99%

Reliable non-destructive strength assessment in existing structures: myth or reality?

Breysse

Balayssac

2019

RILEM Tech Lett

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The non-destructive assessment of concrete strength in existing structures is a complex issue which has been analyzed by a recently closed RILEM committee (TC 249-ISC) whose Guidelines and Recommendations are to be released soon. This committee has considered the state of practice, the yet existing standards and most recent innovative research results, in order to write recommendations that would improve the reliability of strength assessment with non-destructive techniques (NDT). These recommendations are based on a paradigm change: the challenge is not that of finding the true local strength, but that of estimating its value with a controlled tolerance interval and a limited risk of being wrong. Three levels of requirements are defined which correspond to different tolerance intervals on the assessed parameters and to a different amount of resources devoted to the investigation. While most of research has been devoted until now to the identification of relevant conversion models between NDT test results and strength, we have shown that the priority had to be put on other items, including the assessment of the NDT test results repeatability, the relevant definition of core locations and the checking of the final predictive error. This paper briefly describes the main innovations included in these recommendations.

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“…Accounting for the frequent large variability of concrete strength within a single building, a procedure for identifying homogenous areas is proposed in Reference [17], based on a first investigation phase made up of in situ, non-destructive tests. The results of these tests allow the definition of an effective, although as limited as possible, campaign of core drilling.…”

Section: Introductionmentioning

confidence: 99%

Analysis of a Large Database of Concrete Core Tests with Emphasis on Within-Structure Variability

2019

Self Cite

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In reinforced concrete (RC) structures, the compressive strength of concrete can play a crucial role in seismic performance and is usually difficult to estimate. Major seismic codes prescribe that concrete strength must be determined essentially from in situ and laboratory tests. Mean values obtained from such tests are the reference design values when assessing existing structures under seismic actions. The variability of concrete strength can also play an important role, generally requiring that various homogeneous domains are identified in a single structure, in each of which a specific mean value should be assumed as representative. This study analyzes the inter- and intra-variability of the concrete strength of existing buildings using a very large database made up of approximately 1600 core tests extracted from RC buildings located in the Basilicata region (Southern Italy). The analysis highlighted that concrete strength variability was dependent on the structures’ dimensions as well as on the number of storeys. Moreover, the concrete strength of cores extracted from columns was found to be, on average, lower than that from beams, thus justifying the usual practice to extract cores mainly from columns, which results in a conservative approach as well as a more feasible one. Finally, some case studies were analyzed, specifically focusing on the effects of the within-storey variability. Conservative strength values, to be used especially in the case of vertical members subjected to high axial loads, are suggested.

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Criteria for identifying concrete homogeneous areas for the estimation of in-situ strength in RC buildings

Cited by 37 publications

References 13 publications

Estimation of Compressive Strength of High Strength Concrete Using Non-Destructive Technique and Concrete Core Strength

Estimation of Compressive Strength of High Strength Concrete Using Non-Destructive Technique and Concrete Core Strength

Reliable non-destructive strength assessment in existing structures: myth or reality?

Analysis of a Large Database of Concrete Core Tests with Emphasis on Within-Structure Variability

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