Assessment of in-situ compressive concrete strength by means of various non/semi-destructive and destructive techniques

For rehabilitation of existing concrete structures, knowing the strength of the different elements is mandatory. According to EN 13791, the assessment of the compressive strength of ‘old’ structures, that are to be modified, can be performed by (i) destructive testing of drilled cores with varying amounts depending on the involved concrete volume and the test purpose, and (ii) calibrated indirect methods by combining destructive core drilling with non- or semi-destructive techniques. The use of core-drilling is a time-consuming method that is labor-intensive and weakens the existing concrete structure, leaving a lasting impression on the concrete structure. As an alternative, many different non- and semi-destructive techniques are available for the in-situ determination of compressive strength. An experimental program is conducted on 7 concrete slabs intended for various exposure classes (according to EN206-1 and NBN B15-001). The techniques, besides destructive core drilling and testing (according to EN 12504-1), that were used in this study are the rebound hammer, the ultrasonic pulse velocity tester and the Windsor probe. This study will investigate the possible correlation between the output of these different techniques and the destructively determined compressive strength. The study showed that the technique that provided the most promising results in determining the insitu strength was the semi-destructive Windsor probe. However, by combining the ultrasonic pulse velocity or the Windsor probe with the rebound hammer (the SonReb-method or PenReb-method respectively), also promising results were obtained.

ISBN:9782351581599

Publication year:2017

Accessibility:Open