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concrete from which excess water and entrapped air are extracted by a vacuum process before setting occurs.
a process for increasing the moisture content of lightweight aggregate by subjecting it to a vacuum in a sealed chamber, flooding the chamber with water, and releasing the vacuum.
paper bag for cement or other material, either glued or sewn, made of four or five plies of kraft paper and completely closed except for a self-sealing paper valve through which the contents are introduced and released.
membrane located under a concrete floor slab that is placed on the groundto retard transmission of water vapor.
the pressure exerted when a vapor is in equilibrium with its liquid or solid form at a given temperature.
a membrane that impedes the transmission of gas molecules.
an apparatus for measuring workability of very low-slump or no-slumpconcrete, including a vibrating table, a sample container, and other ancillary items, that permits measurement of the time (vebe time) required to be consolidated in a mold.
liquid carrier or binder of solids.
a masonry facing that is attached to the backup, but not so bonded as to act with it under load.
a cylindrical or annular mixing compartment having an essentially level floor and containing one or more vertical rotating shafts to which blades or paddles are attached; the mixing compartment may be stationary or rotate about a vertical axis.
concrete consolidated by vibration during and after placing.
energetic agitation of freshly mixed concrete during placement by mechanical devices, either pneumatic or electric, that create vibratory impulses of moderately high frequency to assist in consolidating the concrete in the form or mold. (1) external vibra
the age at which fresh concrete has undergone a sufficient degree of setting and developed adequate strength to resist flow when subjected to vibration.
an oscillating machine used to agitate fresh concrete so as to eliminate gross voids, including entrapped air but not entrained air, and to produce intimate contact with form surfaces and embedded materials. (See also vibration.)
a penetration device used in the testing of hydraulic cements and similar materials.
a weighted needle for determining time of setting of hydraulic cements.
instrument for determining viscosity of slurries, mortars, or concretes.
a measure of the resistance of a fluid to deform under shear stress.
volumetric ratio of air plus net mixing water to cement in a concrete or mortar mixture.
material that is subject to release as a gas or vapor; liquid that evaporates readily.
combining the constituents of mortar or concrete based on volumetric measurement. (See also volumetric measuring.)
an increase or decrease in volume due to any cause. (See alsodeformation and time-dependent deformation.)
dispensing an ingredient based on volume, either in discrete quantities orby continuous flow.
equipment that uses measurements based on the volumes of the ingredients to feed a container that continually agitates and combines those ingredients for the production of concrete (also called volumetric- measuring and continuous-mixing concrete equipmen
