Study of the Effect of Blended Coarse Aggregate on Air Entrained Concrete

This research with combined coarse aggregates in cement concrete was initiated at the request of the Director of Design as a direct result of the condition study made by the Division of Design in 1945. In the report on this study it was shown that on the basis of averages pertaining to 80 projects with crushed limestone totalling about 395 miles in length, and 70 projects with Ohio River Gravel totalling approximately 410 miles in length, the service record for pavements with the river gravel was far inferior to that of pavements containing limestone coarse aggregate. Specifically, the summary of data showed that pavements with the gravel had an average of seven times as many outside corner breaks, more than eight times as many inside corner breaks, and almost elevent time sas many blow-ups per mile as the pavements with crushed limestone; furthermore, the average transverse crack and joint interval in the former was only about 0.6 as long as that in the latter