In this paper, methods of testing the drying shrinkage of concrete blocks are evaluated. Tests were done on blocks of differing strengths, suppliers and curing procedures. The shrinkage tests were carried out as recommended in ASTM C426 [1], using the whole block as specimens and with gauge discs attached to the sides. Three variations of this set-up were also tested: a face-shell prism cut from a whole block with gauge plugs attached to the sides, the same specimen with gauge discs attached to the top and bottom and whole blocks with gauge discs attached to the top and bottom. For the case of gauge discs attached to the sides, a Humboldt strain gauge was used to measure deformation. In the case of gauge discs attached to the top and bottom, a comparator was used. Deformations on control blocks left inside the laboratory, and not submitted to the saturated and dry conditions of the ASTM C426 test, were also measured for nearly 90 days.
