ASTM C1579-21 PDF Download

ASTM C1579-21 is a standard test method that aims to evaluate the plastic shrinkage cracking of restrained fiber reinforced concrete using a steel form insert. The test is designed to assess the effects of evaporation, settlement, and early autogenous shrinkage on the performance of the concrete.

The measured values obtained from this test can be used to compare different concrete mixtures, including those with and without fibers, as well as those containing various amounts of different types of fibers and admixtures. The evaporation conditions during the test should be sufficient to produce an average crack width of at least 0.5 mm in the control specimens, and the evaporation rate from a free surface of water should be within ±5% for each test.

It is important to note that this test method attempts to control atmospheric variables in order to quantify the relative performance of a given fresh concrete mixture. However, it is also acknowledged that other variables such as cement fineness, aggregate gradation, mixing procedures, and concrete temperature can influence potential cracking. Therefore, efforts should be made to keep these variables as consistent as possible from mixture to mixture during testing.