| 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 Resistance | (Concrete Engineering) Ability of cement paste, aggregate, or mixtures thereof to withstand sulfate attack. |
| Temperature Rise | (Concrete Engineering) The increase of concrete temperature caused by heat of hydration and heat from other sources. |
| 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. |
| Truck Mixer | (Concrete Engineering) A concrete mixer capable of mixing concrete in transit when mounted on a truck chassis. |
| Unit Water Content | (Concrete Engineering) The quantity of water per unit volume of freshly mixed concrete, often expressed as gallons or pounds per cubic yard. This is the quantity of water on which the water cement ratio is based, and does not include water absorbed by the aggregate |
| Vapor Pressure | (Concrete Engineering) The pressure exerted by a vapor that is calculated based upon relative humidity and temperature. The higher the humidity and higher temperature, in degrees Fahrenheit, the greater the vapor pressure exerted. |
| Vaporproof | (Concrete Engineering) A material that is totally immune to the passage of a gas under pressure. Any material that is truly vaporproof will inherently be waterproof. |
| 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. |