Certain directions in several cement specifications appear to mandate a fixed mass of cement for (lab) trial batches. If a specific mass of material is called for, it may be more or less than the intended volume of material, setting up a potential conflict in the directions. The mass of cement for mixing trial batches in the lab was always intended to be dependent on the bag weight of the material, as this can vary from one product to another. To correct this confusion, remove the statements that set an exact mass for a given volume of plastic cement and replace this with a statement to obtain bulk density from the bag or material supplier in order to determine the correct mass of cement for trial batches. Because the calculation example is non-mandatory information, delete the note from the body of the text and place it in a new appendix along with explanatory language.
plaster; plastic cement; portland cement-based plaster; stucco;
Citing ASTM Standards
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