Non-destructive tests (NDT) are widely used and play an important role in engineering projects including newly constructed and existing structures. For new structures, applications are mainly quality control or the resolution of doubts about the quality of materials or construction. Testing of existing structures is related to the assessment of structural integrity or adequacy.
Commonly, these tests are done without damaging concrete. These tests can be used to determine a broad range of concrete properties such as density, elastic modulus, strength, surface hardness and absorption, reinforcement location, size and distance from the surface.
Applications and Importance of Non-destructive Tests on Concrete
- Situations in which non-destructive testing is used are presented below:
- Assessment of the quality of construction like in situ constructions and precast units.
- Evaluate the location and the extent of defects such as honeycombing, cracks, voids, and other defects within concrete elements.
- Ensure the acceptability of materials supplied in case of apparent non-compliance with the specification.
- Monitoring strength development of concrete in relation to formwork removal, cessation of curing, prestressing, load application, and other similar activities.
- Confirm or negate any doubts concerning the workmanship involved in batching, mixing, placing, compacting, or curing of concrete.
- Specify the position and condition of steel reinforcements.
- Increase the level of confidence of smaller number of destructive tests.
- Evaluate the potential durability of concrete.
- Locating and/or confirming suspected concrete deterioration due to overloading, fire, explosion, fatigue, external or internal chemical attack or change, and environmental effects.
- Monitor long term changes in concrete properties.
- Determine the extent of concrete variability so as to help in the selection of sample locations representative of the quality to be assessed.
- Obtain information for any suggested changes of use of a structure for insurance or for change of ownership.
- Specify the concrete uniformity, possibly preliminary to core cutting, load testing, and other more expensive or disruptive tests