| 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. |
| 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. |
| 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. |
| Temper | (Concrete Engineering) The addition of water to the cement mix whether at the batch plant, during transit or at the jobsite to achieve the specified water to cement ratio. |
| Tilt-up | (Concrete Engineering) A method of concrete construction such as where members are cast horizontally near their eventual position, usually on a recently placed slab, and then tilted into place after removal of forms. |
| Transit-Mixed Concrete | (Concrete Engineering) Concrete produced from a central-batching plant, where the materials are proportioned and placed in truck-mixers for mixing enroute to the job or after arrival there. |
| Truck Mixer | (Concrete Engineering) A concrete mixer capable of mixing concrete in transit when mounted on a truck chassis. |
| Vibration | (Concrete Engineering) Energetic agitation of concrete to assist in its consolidation, produced by mechanical oscillating devices at moderately high frequencies. (A.) External vibration employs a device attached to the forms and is particularly applicable to the manufacture of precast items and for the vibration of tunnel lining forms. (B.) Internal vibration employs an element which can be inserted into the concrete; and is more generally used for cast-in-place construction. |
| Water-Cement Ratio | (Concrete Engineering) The ratio of the amount of water, exclusive of that absorbed by the aggregates, to the amount of cement in a concrete mix. Typically expressed as percentage of water, by weight in pounds, to the total weight of portland cement, fly ash, and any other cementitious material, per cubic yard, exclusive of any aggregates. |