1.1 This specification pertains to five classes of blended hydraulic cements for both general and special applications, using slag or pozzolan, or both, with portland cement or portland cement clinker or slag with lime. Note 1—This specification prescribes ingredients and proportions, with some performance requirements whereas Performance Specification C 1157 is a blended cement specification in which performance criteria alone govern the products and their acceptance. 1.2 For properties where values are given in both SI and non SI units, the values in SI units are to be regarded as the standard. Values in SI units shall be obtained by measurement in SI units or by appropriate conversion, using the Rules for Conversion and Rounding given in Standard IEEE/ASTM SI 10, of measurements made in other units. 1.3 The text of this standard refers to notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) are not requirements of the standard.