Crack Width Meter cards are useful for spot checks of crack width during construction.
Crack measurement during construction is primarily undertaken as a quality control measure during the initial curing of concrete.
The process of crack mapping will typically document the layout of cracks visible in a concrete element, perhaps their path or highlighting them in a photographic record.
Crack Width Meter cards provide an initial measurement of crack width, suitable for pass/fail assessment, where a precision measurement is required a measuring magnifier or camera may be more appropriate.