scope:

Nondestructive testing (NDT) methods are used to determine concrete properties and to evaluate the condition of concrete in deep foundations, bridges, buildings, pavements, dams, and other concrete construction. For this report, NDT is defined as generally noninvasive, with the exception of transport property tests, which may cause easilyrepaired surface damage. While coring and load testing may be considered nondestructive, they are excluded from this report. Refer to ACI 437R for more information about strength evaluation of existing concrete buildings.

NDT methods are applied to concrete construction for four primary reasons:

1. Quality control of new construction

2. Troubleshooting problems with new and old construction

3. Condition evaluation of older concrete for rehabilitation purposes

4. Quality assurance of concrete repairs

NDT technologies are evolving and research continues to enhance existing methods and develop new methods. The report is intended to provide an overview of the principles of various NDT methods practiced and to summarize their applications and limitations. Emphasis is placed on methods that have been applied to measure physical properties other than the strength of concrete in structures, to detect flaws or discontinuities, and to provide data for condition evaluation. Methods to estimate in-place compressive strength are presented in ACI 228.1R.