ASTM C806-18 PDF Download

The ASTM C806-18 standard outlines the procedure for measuring the length changes of expansive cement mortar under restraint. The test is conducted to determine the expansion or contraction of the mortar due to the internal forces generated by cement hydration.

The test apparatus described in the standard includes molds for casting test specimens, a restraining cage consisting of a threaded steel rod with end plates, a length comparator, a tamper made of nonabsorptive material, a device for demolding specimens, weights and weighing devices, glass graduates for measuring mixing water, an electric mixer with paddle and mixing bowl, and a trowel with a steel blade.

The standard provides detailed instructions for the preparation and assembly of specimen molds and restraining cage, as well as the proportioning and mixing of mortars. It also covers the procedures for molding and curing the specimens. The expansion and shrinkage of the test specimens at various ages are calculated and reported as linear expansion or contraction based on the length of the specimen at the time of molding.

The standard also addresses bias and precision in batch, single, and multi-laboratory operations. It includes references to notes and footnotes that provide additional explanatory information, but these notes and footnotes are not considered as requirements of the standard.