ASTM C494/C494M-19 PDF Download

ASTM C494/C494M-19 is a standard specification that outlines the materials and test methods used for chemical admixtures added to concrete mixtures. The specification covers seven types of admixtures: Type A - water reducing, Type B - retarding, Type C - accelerating, Type D - water reducing and retarding, Type E - water reducing and accelerating, Type F - water reducing, high range, and Type G - water reducing, high range, and retarding.

The standard specifies that the concrete mixtures must include Type I or Type II cement, pozzolan, fine and coarse aggregates, and air-entraining admixture. Various tests are conducted on samples of freshly mixed concrete, such as slump, air content, time of setting, and water content tests. Physical properties retesting includes uniformity and equivalence tests, infrared analysis, residue by oven drying, and specific gravity determination.

For qualifying an admixture, test specimens are made using concreting materials as described in the standard. Supplementary tests are recommended to be conducted by the purchaser using the specific materials and mixture proportions proposed for the specific work. The specification provides three levels of testing: Level 1 for initial approval, Level 2 for limited retesting, and Level 3 for acceptance of a lot or measuring uniformity.

It is important to note that the standard includes additional notes that provide explanatory material, but these notes are not considered as requirements of the standard. The purchaser should also verify the equivalence of the admixture supplied for use in the work and its compatibility with reinforced concrete, as admixtures containing sufficient amounts of chloride may accelerate corrosion of steel reinforcement.