Collection of ENEA technology and expertise
Non Destructive in situ strength assessment of concrete
The relationship between the compressive strength of concrete measured by mechanical testing and measurements obtained by in-situ non-destructive testing (NDE) is not easily correlated to date. A new method for selecting the location of test points from which cores are to be extracted has been validated to minimise the risk of error in strength assessment. Such an approach makes it possible to elevate the use of NDEs from a means of strength assessment to an active tool on the basis of which the definition of the core points of a structure can be set
Detailed steps of the recommended concrete assessment process in situ
Application sectors
Problem to solve
The Laboratory Technologies for the Preservation of Architectural and Cultural Heritage has long been engaged in research and development activities on some relevant and topical issues in civil engineering, such as the definition of methods for estimating the strength of concrete and the possibility of using Non-Destructive Testing alongside traditional destructive testing (which is costly and very invasive) to measure the in-situ strength of materials. To deal with these issues, introduced by the technical regulations, it is necessary to collect experimental data in statistically significant numbers and then translate the results into models for predicting the strength of concrete and correlating destructive tests (compression mechanical strength of extracted cores) and non-destructive tests to carry out an analysis of the state of reinforced concrete structures in situ.
Description
In an investigation process aimed at verifying the ‘health' conditions of a building, as a function of the project to implement its performance characteristics and adapt to current regulations, it is necessary to take into account the complex nature of the building organism in which the material, structural, technological and plant engineering components are closely correlated and integrated. The seismic assessment and adaptation of existing buildings is an operation for which the current Italian and European regulations do not provide decisive indications on how to perform the tests: a minimum number of destructive tests to be performed is defined, but freedom is left on the location of the core samples and the possible use of PND. The objective of this methodology is to validate the use of non-destructive tests through the identification of reliable correlation curves, i.e. to correlate the ultrasonic velocity and/or rebound index with the characteristic compressive strength of the concrete, thus reducing the number of destructive tests to be carried out on the structure under investigation. The RILEM Recommendations developed within the Technical Committee ‘ISC on non destructive in situ strength assessment of concrete' have new points which can be summarised as follows: -a procedure has been identified which allows the prediction capability of the compressive strength of concrete to be defined as a function of the quality of the selected PND which influences the error made in the assessment. The choice of the quality of the measurements to be carried out strongly depends on how much is to be invested in the PND plan. It is clear from the studies carried out that the more one invests in the quality of the NDT campaign, in a preventive manner, the more one can reduce the number of cores to be cored, thus decreasing the risk of error.
Innovative aspects and advantages
- Minimise diagnostic investigation time on the structure
- Minimise the number of cores when assessing the compressive strength of concrete
- Minimise the risk of error when evaluating the compressive strength of concrete
- Reduce the costs of structure investigation
Technological Maturity 7
Strengths
- Cost
- Social/economic relevance
- Legal/regulatory content
- Efficiency/productivity/performance
- Innovation
- Lack of technology/solution for the specific task
- Scalability
- Ease of use
- Transferability/mobility
- Processing/feed-back times
Admissible applications
- Development of innovative non-destructive testing technologies and methodologies for the verification of reinforced concrete structural elements of buildings that have suffered disruptive events, e.g. earthquakes, to enable appropriate rehabilitation
- Development of non-destructive testing methodologies for inspections as required by the guidelines for risk classification and management, safety assessment and tunnel monitoring
- Integrated structural and energy instrumental diagnosis to be used on buildings in order to minimise, and thus economise, input times. This diagnosis provides the information to build a reliable BIM
Research group involved
Patent Available for Licensing
Non disponibile per una licenza
Revision date
27-06-2025
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