The following are suggested mix proportions only and actual batch quantities should be established based upon laboratory prepared trial mixtures using materials intended for use on a specific project. These concrete mix proportions are based on the use of an air-entraining admixture conforming with the requirements of Standard Specification for Air Entraining Admixtures for Concrete, ASTM Designation: C260, and a water reducing admixture conforming with the requirements of Standard Specification for Chemical Admixtures for Concrete, ASTM Designation: C 494. These concrete mix proportions are based on sand in a saturated surface dry condition (SSD) and Norlite coarse and fine aggregate in an oven dry condition. Adjustments in aggregate and water quantities must be made based on the actual moisture content of the aggregates at the time of batching. Since Norlite normally contains from 4 to 8 percent moisture as shipped, batched weights per cubic yard of concrete will vary according to the moisture content, which may be as high as 25%.
The mix designs in the following pdf are based upon an estimated active water demand. That portion absorbed by the aggregate is not considered for determining yield since it has no volumetric effect. Due to the absorbed condition this water is not available to affect the cement paste. Therefore, as noted in ASTM C 125 (Concrete and Concrete Aggregates), absorbed water is not considered when calculating the water-cement ratio.
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