4.1 Supplementary cementitious materials (SCM) covered under existing ASTM specifications are fly ash, slag cement, raw and calcined natural pozzolans including calcined clays, silica fume, and ground-glass pozzolan. The use of these materials, and limits established in existing specifications, are based on data obtained from research programs, field testing, and long term performance monitoring. Performance of SCM in specific concrete mixtures is commonly verified through preconstruction testing. This guide provides an approach to assessing the properties of materials that are not covered under existing specifications, and for assessing the performance of those materials in concrete.

4.2 If an ASCM does not yet have a significant record of performance in concrete, a comprehensive evaluation based on this Guide should be undertaken, and it should be recognized that this ASCM might be introduced for a specific project or into a limited marketplace to initially demonstrate its performance. The user should bear in mind the intended end use of the ASCM and use appropriate test methods to establish its suitability. An ASCM that demonstrates good performance through a comprehensive evaluation as outlined in this guide could then be considered to have access to broader markets and could be considered for inclusion in an ASTM standard for SCM. For this reason, the test program to demonstrate acceptable performance should include concrete mixtures with a range of characteristics specific to the ASCM's intended use.

4.3 In the absence of long-term durability or acceptable field performance, prospective users are advised to apply appropriate risk management and engineering practice in the use of an ASCM.