ISO 22904:2020

Additions for concrete

Scope

This document specifies requirements for the properties for silica fume, siliceous fly ash and ground granulated blastfurnace slag for use as a type II addition for production of concrete conforming to ISO 22965. Additions according to this document can also be used in mortars and grouts.
This document applies to the silica fume which is a by-product of the smelting process used to produce silicon metal and ferro-silicon alloys.
Fly ash produced with other types or higher percentages of co-combustion materials than those provided for in this document is outside the scope of this document.
Ground granulated blastfurnace slag containing any added materials other than grinding aids and/or gypsum (calcium sulfate) is not within the scope of this document.
It is not within the scope of this document to specify provisions for the practical application of additions in the production of concrete, mortar or grout, i.e. requirements concerning composition, mixing, placing, curing, etc.
NOTE Some rules are given in ISO 22965‑2, e.g. provisions on general suitability and use of additions. Guidance on batching, control of additions content and the use of the k-value concept are also given in ISO 22965‑2.

National adoptions