ClipArt ETC
"Single-course pavement is usually made five inches thick. Proportions for this should be 1:2:3. Concrete for a single course should be mixed to such a consistency that enough mortar will rise to the surface on light tamping to permit of finishing with a wooden float."—The Federal Digest, 1921

One-Course Work

"Single-course pavement is usually made five inches thick. Proportions for this should be 1:2:3. Concrete…