The geology of sands and aggregates for concrete making with especial reference to texture

The essential constituents of concrete are the aggregate, or lumps of broken materials, and the matrix, or binding substance, which is usually cement or lime. Frequenty sand is also added to the mixture, or a fine-grained concrete may be made from sand and cement alone. The American connotation of the term "aggregate" includes sand. P. G. H. Boswell