S1 This specification covers ready-mixed concrete manufactured and delivered to a purchaser in a freshly mixed and unhardened state as hereinafter specified. S2 Requirements for quality of concrete shall be either as hereinafter specified or as specified by the purchaser. S3 In any case where the requirements of the purchaser differ from these in this specification, the purchaser's specification shall govern. S4 This specification does not cover the placement, consolidation, curing, or protection of the concrete after delivery to the purchaser.