26.4.3 Proportioning of Concrete Mixtures
(1) Can be placed readily without segregation into forms and around reinforcement under anticipated placement conditions.
(3) Conforms to strength test requirements for standard-cured specimens.
(b) Concrete mixture proportions shall be established in accordance with Article 4.2.3 of ACI 301 or by an alternative method acceptable to the licensed design professional. Alternative methods shall have a probability of satisfying the strength requirements for acceptance tests of standard-cured specimens that meets or exceeds the probability associated with the method in Article 4.2.3 of ACI 301. If Article 4.2.3 of ACI 301 is used, the strength test records used for establishing and documenting concrete mixture proportions shall not be more than 24 months old.