Nondestructive Assessment of the Actual Compressive Strength of High-Strength Concrete

摘要

This paper deals with nondestructive testing of high strength concrete. An experimental program was carried out, involving both destructive and nondestructive methods applied to different concrete mixtures, with cube strength varying from 30 up to 150 MPa. Relationships were derived for pulse velocity, rebound hammer, pull-out, probe penetration, microcoring, and combined methods. The results show good behavior for some methods, like pulse velocity, rebound hammer, and combined SonReb methods. By keeping the analytical form of the relationship usually adopted for normal-strength concrete unchanged, only the constants have been changed for these methods. Some problems arose with the pull-out and probe penetration tests, for which the available commercial testing systems are not adequate at very high strength levels. The relationships for the various methods were compared in terms of dimensionless sensitivity, for different strength levels. The results showed decreasing sensitivity, with increasing strength.