ASTM C61/C61M-00 (R2020) PDF Download

The ASTM C61/C61M-00 (R2020) standard covers different grades of anhydrous calcined gypsum known as gypsum Keene's cement. This cement is specifically designed for use in the base and finish coats of gypsum plaster. The standard specifies that the cement should have a combined water content that does not exceed the specified value when tested according to the referenced test method.

In addition to the water content requirement, the standard also outlines the physical properties that the cement must conform to. It mandates testing for setting time, compressive strength, and fineness of the cement.

The specification highlights that Keene's cements are available in quick-setting and standard-setting types, with various grades of different fineness and setting time. However, for grades intended for special purposes like scagliola castings, these grades should meet all the requirements of the standard, except for fineness and setting time.

The standard allows for the use of either inch-pound or SI (metric) units, with both systems treated separately and not combined. It also includes notes and footnotes that provide additional explanatory information but are not considered as requirements of the standard.