scope:

Nondestructive test (NDT) methods are used to determine hardened concrete properties and to evaluate the condition of concrete in deep foundations, bridges, buildings, pavements, dams and other concrete construction. For this report, nondestructive testing is defined as testing that causes no structurally significant damage to concrete. While some people regard coring and load testing as nondestructive, these are not considered in this report, and appropriate information is given in ACI 437R.

Nondestructive test methods are applied to concrete construction for four primary reasons:

• quality control of new construction;

• troubleshooting of problems with new construction;

• condition evaluation of older concrete for rehabilitation purposes; and

• quality assurance of concrete repairs.

Nondestructive testing 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 being used in practice, and to summarize their applications and limitations. The 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.