Testing on site
Testing on site is normally confined to assessing the compliance of the concrete with its required fresh properties i.e. workability, as it arrives from the batching plant (ready-mixed or onsite set-up). This is usually done by taking a sample of the fresh concrete for workability testing and for the making of standard test specimens (cylinders or cubes) for compressive strength testing.
On-site tests can be carried out on the hardened concrete of the structure itself. These are generally categorised as non-destructive or destructive although the distinction between these is blured as most tests damage the surface to some extent.
These tests assess the properties of the in-situ concrete, e.g. strength, permeability etc. or the integrity of the concrete e.g. concrete cover to the reinforcement, position of the reinforcement, reinforcement corrosion potential, position of voids etc.
Samples can be taken from the structure (lumps, cores) and tested in a laboratory, generally off-site, for constituents or mechanical properties. Where structural integrity is under suspicion, full scale in-situ load tests on elements can be undertaken.