| Revibration | (Concrete Engineering) Delayed vibration of concrete that has already been placed and consolidated. Most effective when done at the latest time a running vibrator will sink of its own weight into the concrete and make it plastic and workable again. |
| Rock Pocket | (Concrete Engineering) Area or portion of hardened concrete which is deficient in mortar and consisting primarily of coarse aggregate and open voids; caused by insufficient consolidation or separation during placement, or both; by leakage from form. |
| Sack | (Concrete Engineering) A quantity of cement: 94 Ibs. in the United States, 87.5 Ibs. in Canada, for portland or air entraining portland cement, or as indicated on the sack for other kinds of cement. |
| Sacking | (Concrete Engineering) Removing or alleviating defects on a concrete surface by applying a mixture of sand and cement to the moistened surface and rubbing with a coarse material such as burlap. |
| Saponification | (Concrete Engineering) The deposit of a gray scum or gray dust on the inside surface of a subgrade wall or floor; as the result of moisture moving through the concrete and washing certain chemicals from the concrete mass. |
| Screen (or Sieve) | (Concrete Engineering) A metallic sheet or plate, woven wire cloth, or similar device, with regularly spaced openings of uniform size, mounted in a suitable frame or holder for use in separating material according to size. |
| Slip Form | (Concrete Engineering) A form which is raised or pulled as concrete is placed; may move vertically to form wails, stacks, bins or silos, usually of uniform cross section from bottom to top; or a generally horizontal direction to lay concrete evenly for highways, on slopes and inverts of canals, tunnels, and siphons. |
| Slump Cone | (Concrete Engineering) A metal mold in the form of a truncated cone with a top diameter of 4”, a bottom diameter of 8”, and a height of 12”, used to fabricate the specimen for a slump test. |
| Spall | (Concrete Engineering) A fragment, usually of flaky shape, detached from a larger mass by pressure, expansion from within the larger mass, a blow, or by the action of weather. |
| Stucco | (Concrete Engineering) A portland cement mortar material that can be applied to the surface of any building or structure to form a hard and durable covering for the exterior wails or other exterior surfaces. |