surface active —having the ability to modify surface energy and to facilitate wetting, penetrating, emulsifying, dispers- ing, solubilizing, foaming, frothing, etc., of other substances. surface-active agent —agent, surface-active. surface air voids —small regular or irregular cavities, usual- ly not exceeding 15 mm in diameter, resulting from en- trapment of air bubbles in the surface of formed concrete during placement and consolidation. (See also sack rub .) surface area —see surface, specific . surface bonding (of masonry) —bonding of dry-laid mason- ry by parging with a thin layer of fiber-reinforced mortar. surface moisture —see moisture, surface . surface retarder —see retarder, surface . surface tension —an internal molecular force that exists in the surface film of all liquids and tends to prevent the liq- uid from flowing. surface texture —degree of roughness or irregularity of the exterior surfaces of aggregate particles and also of hard- ened concrete. surface vibrator —see vibrator, surface . surface voids —see voids, surface . surface water —see moisture, surface (preferred term). surfactant —a shortened form of the term “surface-active agent.” surkhi —a pozzolan consisting of burned clay powder prin- cipally produced in India. sustained modulus of elasticity —see modulus of elastici- ty, sustained . sway brace —a diagonal brace used to resist wind or other lateral forces. (See also bracing ; cross bracing ; and X- brace .) swelling —increase in either length or volume. (See also contraction ; expansion ; volume change ; and volume change, autogenous .) swift —a reel or turntable on which prestressing tendons are placed to facilitate handling and placing. swirl finish —see finish, swirl . Swiss hammer —see hammer, rebound (preferred term). syneresis —the contraction of a gel, usually evidenced by the separation from the gel of small amounts of liquid; a pro- cess possibly significant in the bleeding and cracking of fresh hydraulic-cement mixtures. syngenite —potassium calcium sulfate hydrate, a compound sometimes produced during hydration of portland ce- ment, found in deteriorating portland-cement concrete and said to form in portland cement during storage by re- action of potassium sulfate and gypsum. system — system, one-way —the arrangement of steel reinforce- ment within a slab that presumably bends in only one direction. system, two-way —a system of reinforcement; bars, rods, or wires placed at right angles to each other in a slab and intended to resist stresses due to bending of the slab in two directions. Système International —see SI . systems building —see industrialized building . T T & G —see tongue and groove . table, flow —a flat, circular jigging device used in making flow tests for consistency of cement paste, mortar, or con- crete. (See also flow, ).
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- Winter '18
- The American, ACI Committee, preferred term