本规范涵盖了高反应性火山灰，用作硅酸盐水泥混凝土和砂浆中的矿物外加剂，用于填充小空隙和/或需要火山灰作用的地方。高反应性火山灰是一种粒度比硅酸盐水泥小一到两个数量级的硅微粉产品。这些材料通常以未加密或加密的干燥形式提供。如果材料是以致密形式提供的，则在加工成致密形式之前，应在收集的未致密材料上进行试验。 本标准不适用于规定硅粉。建议使用M 307或ASTM C 1240。

This specification covers high-reactivity pozzolans for use as a mineral admixture in portland cement concrete and mortar to fill small voids and/or where pozzolanic action is desired. High-reactivity pozzolans are microsilica products with a particle size typically one to two orders of magnitude smaller than portland cement. These materials are usually supplied in undensified or densified dry form. If the material is supplied in a densified form, the tests should be performed on the as-collected undensified material before being processed into densified form.This standard is not intended for specifying silica fume. It is recommended that M 307 or ASTM C 1240 be used for that purpose.