ISO 679:2009 specifies a method of determining the compressive and, optionally, the flexural strength of cement mortar containing one part by mass of cement, three parts by mass of ISO standard sand and one half part of water. ISO 679:2009 applies to common cements and to other cements and materials, the standards for which call up this method. ISO 679:2009 might not apply to other cement types that have, for example, a very short initial setting time.

ISO 679:2009 describes the reference equipment and procedure and specifies the method used for validation testing of ISO standard sands and of alternative equipment and procedures.