In many areas of the country, river and natural sands are becoming depleted. This, coupled with vastly improved production techniques by stone producers, has made stone sand an attractive option for concrete producers.
Stone sand is a fine aggregate processed from quarried stone that is crushed and classified to obtain a controlled gradation and a cubical to angular particle shape. This angular shape gives cement paste a good surface to bond. To be effective, stone sand should be made from a non-porous, durable rock.
Mix designs need to be modified for the specific gravity of the stone sand, according to ACI 211.1. In order to use stone sand on specification work, approval from the project architect or engineer is needed. Samples and statistics should be available for their approval. Successful use of stone sand in portland cement concrete requires cooperation and acceptance of contractors and finishers. Their concern will be with the workability, finishability, pumpability, and bleeding characteristics of the plastic concrete. A stone sand that is properly crushed and graded should not have a negative effect on these characteristics.