| 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. |
| Sand (ASTM C125) | (Concrete Engineering) That portion of an aggregate passing the No. 4 (4.76 mm) sieve and predominantly retained on the No. 200 (74 micron) sieve. |
| 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. |
| Sulfate Attack | (Concrete Engineering) Deleterious chemical and/or physical re-action between sulfates in ground water or soil and certain constituents in cement, which result in expansion and disruption of the concrete. |
| Sulfate Resistance | (Concrete Engineering) Ability of cement paste, aggregate, or mixtures thereof to withstand sulfate attack. |