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Description: The American Society for Testing and Materials (ASTM) Test Method C 265 (“Method of Measurement of Calcium Sulfate in Portland Cement Mortar”) has been studied to determine the precision of the test method and search for means to improve it. In a first phase of the project, the particle size fraction for extraction, the method of crushing, and the time allowed for processing the sample were studied. A second phase studied extraction time, water/solid ratio for extraction, curing temperature, and cement sulfate content.
Findings show that none of the studied variables affected the precision of the test method result. Statistical analyses were conducted for the variables investigated in the second phase. Test of hypotheses for equal means (ANOVA) and equal variance (Levene and Bartlett) confirm that the variables tested and their combinations do not affect the standard deviation of test results. This report is also found on DVD021.
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