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"For two-course floors and pavements, a concrete base of about four inches thick, mixed 1:3:5 (that is, one sack of cement, 3 cubic feet of sand, and 5 cubic feet of gravel), is first placed in the forms."—The Federal Digest, 1921

Two-Course Work

"For two-course floors and pavements, a concrete base of about four inches thick, mixed 1:3:5 (that…