Non-destructive testing for in-place strength estimation of concrete masonry units

The production factories of concrete masonry units (CMUs) mostly rely on destructive testing as per ASTM C140([1]) for quality assurance. Such testing is expensive and is, therefore, performed on a limited basis. This research investigates the prospects of using non-destructive tests with the rebound hammer and ultrasonic pulse velocity for evaluating the compressive strength of concrete specimens made with materials, mixture proportions and compaction representative of CMUs. A statistical analysis of the testing data shows that these non-destructive testing techniques are not equally reliable. It is concluded that pulse velocity can be a useful tool for the in-situ strength evaluation of CMUs.