Excess soluble sulfate ions in hardened cement can result in reduced durability. This test method is intended to show whether calcium sulfate has been used in cement in such amount to leave excess soluble sulfate in hardened mortar. The test method is used to establish compliance in Specification C 595 for those cements in which optimized SO₃ exceeds the table limit. This test method also can provide useful information on other hydraulic cements, such as those specified in Specifications C 150 and C 1157.

When this test method is used in conjunction with Test Method C 563, use the appropriate age of test specimens (24 h, 3 days, or 7 days) to coincide with the age of specimens used in Test Method C 563.

1.1 This test method covers the measurement of water-extractable SO₃ in hardened hydraulic cement mortar. This measurement is assumed to represent unreacted, available sulfate remaining in the mortar.

1.1.1 Warning—Fresh hydraulic cementious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 Values in SI units were obtained by measurement in SI units or by appropriate conversion using the Rules for Conversion and Rounding given in IEEE/ASTM SI-10 Standard of measurements made in other units.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.