Aggregates comprise 60 to 75 percent of the total volume of concrete. The type and size of the aggregate mixture depends on the thickness and purpose of the final concrete product. Relatively thin buildings sections can require small coarse aggregates, though aggregates up to six inches (150 mm) in diameter have been used in large dams. A continuous gradation of .
The advantage of small aggregate in the waterratio strength relationship may or may not be sufficient to offset the effects of its higher mixing water demand. It appears that optimum maximum size, so far as strength is concerned, will vary for different aggregates, different cement factors, different test ages and probably other conditions. 4. A realistic appraisal of the recent .