Concrete Waterproofing Glossary
Back Plastering
plaster applied to one face of a lath system following application and subsequent hardening of plaster applied to the opposite face. (See also parge.)
Backfill Concrete
nonstructural concrete used to over-fill excavated pockets in rock or prepare a surface to receive structural concrete. (See also controlled low-strength material [preferred term].)
Backshores
shores placed snugly under a concrete slab or structural member after the original formwork and shores have been removed from a small area without allowing the entire slab or member to deflect or support its own mass or existing construction loads.
Bacterial Corrosion
destruction of a material by bacterial processes brought about by the activity of certain bacteria that consume the material and produce substances, such as hydrogen sulfide, ammonia, and sulfuric acid.
Bag of Cement
a quantity of portland cement: 94 lb (43 kg) in the United States; for other kinds of cement, a quantity indicated on the bag. (Also called sack of cement.)
Balanced Load
load capacity at simultaneous crushing of concrete and yielding of tension steel. (See also load balancing.)
Balanced Moment
moment capacity at simultaneous crushing of concrete and yielding of tension steel.
Balanced Reinforcement
(1) an amount and distribution of reinforcement in a flexural membersuch that in working-stress design, the allowable tensile stress in thesteel and the allowable compressive stress in the concrete are attainedsimultaneously;
(2) an amount and distributi
Ball Mill
horizontal, cylindrical, rotating mill charged with large grinding media.
Ball Test
a test to determine the consistency of freshly mixed concrete by measuring the depth of penetration of a cylindrical metal weight with a hemispherical bottom. (See also Kelly ball.)
Bar
a long, slender structural element, normally composed of steel, used to reinforce concrete.
Bar Bender
(1) a tradesman who cuts and bends steel reinforcement;
(2) a machine for bending steel reinforcement.
Bar Schedule
a list of the reinforcement showing the shape, number, size, and dimensions of every different element required for a structure or a portion of a structure.
Bar Spacing
the distance between parallel reinforcing bars, measured center to center of the bars perpendicular to their longitudinal axes.
Bar Support
hardware used to support or hold reinforcing bars in proper position to prevent displacement before and during concrete placement. (See also slab bolster. )
Bar-end Check
a check of the ends of reinforcing bars to determine whether they fit the devices intended for connecting the bars. (See also mechanical connection.)
Barite
a mineral, barium sulfate (BaSO 4 ), used in either pure or impure form as concrete aggregate primarily for the construction of high-density radiation shielding concrete (also called barytes in the United Kingdom).
Barrel (of Cement)
(obsolete) a quantity of portland cement: four bags or 376 lb in the UnitedStates.
Base
(1) a subfloor slab or working mat, either previously placed and hardened or freshly placed, on which floor topping is placed in a later operation;
(2) the underlying stratum on which a concrete slab, such as a pavement, is placed. (See also mud mat and s
Base Coat
any plaster coat or coats applied before application of the finish coat.
Base Course
(1) a layer of specified select material of planned thickness constructedon the subgrade or subbase of a pavement to serve one or more functions, such as distributing loads, providing drainage, or minimizing frost action;
(2) the lowest course of masonry
Basic Creep
creep that occurs without migration of moisture to or from the concrete. (See also creep and drying creep.)
Bassanite
calcium sulfate hemihydrate, 2CaSO 4 – H 2 O. (See also hemihydrate andplaster of paris.)
Batch
(1) quantity of material mixed at one time or in one continuous process;
(2) to weigh or volumetrically measure and introduce into the mixer the ingredients for a quantity of material.
Batch Mixer
a machine that mixes batches of either concrete or mortar.
Batch Plant
an installation for batching or for batching and mixing concrete materials.
Batch Weights
the quantities of the various ingredients (cement, water, the several sizes of aggregate, and admixtures, if used) that compose a batch of concrete.
Batcher
a device for measuring ingredients for a batch of concrete.
(1) manual batcher – a batcher equipped with gates or valves that areoperated manually, with or without supplementary power (pneumatic,hydraulic, or electrical), the accuracy of the weighing oper
Batten
a narrow strip of wood placed over the vertical joint of sheathing or paneling; also used to hold several boards together (also called batten strip). (See also cleat.)
Beam Test
a method of measuring the flexural strength (modulus of rupture) ofconcrete by testing a standard unreinforced beam.
Beam-column
a structural member subjected to axial load and bending moment.
Beneficiation
improvement of the chemical or physical properties of a raw material or intermediate product by the removal or modification of undesirable components or impurities.
Bent Bar
a reinforcing bar bent to a prescribed shape. (See also hook, hooked bar,stirrup, and tie.)
Bentonite
a clay composed principally of minerals of the montmorillonoid group,characterized by high adsorption and large volume change with wetting or drying.
Binary Mixture
concrete containing two cementitious materials.
Binder
(1) material forming the matrix of concretes, mortars, and sanded grouts;
(2) chemical treatment applied to fibers to give integrity to mats, roving, and reinforcement.
Blaine Apparatus
air-permeability apparatus for measuring the surface area of a finelyground cement, raw material, or other product. See ASTM C204.
Blaine Fineness
the fineness of powdered materials such as cement and pozzolans, expressed as surface area per unit mass usually in square meters per kilogram, determined by the Blaine apparatus. (See also specific surface.)
Blaine Test
a method for determining the fineness of cement or other fine material on the basis of the permeability to air of a sample prepared under specified conditions.
Blast-furnace Slag
the nonmetallic product consisting essentially of silicates and aluminosilicates of calcium and other bases that develops in a molten condition simultaneously with iron in a blast furnace.
(1) air-cooled blast-furnace slag – the material resulting from so
Bleeding
the autogenous flow of mixing water within, or its emergence from, a newly placed cementitious mixture caused by the settlement of solid materials within the mass.
Bleeding Capacity
the ratio of volume of water released by bleeding to the volume of paste or mortar.
Bleeding Rate
the rate at which water is released from a paste or mortar by bleeding.
Blemish
any superficial defect that causes visible variation from a consistently smooth and uniformly colored surface of hardened concrete. (See alsobug holes, efflorescence, honeycomb, lift joint, laitance, popout, rock pocket, and sand streak.)
Blended Cement
a hydraulic cement consisting of portland cement uniformly mixed with slag cement or pozzolan, or both.
Blockout
a space within a concrete structure under construction in which fresh concrete is not to be placed, called core in United Kingdom.
Blowpipe
air jet used in shotcrete gunning to remove rebound or other loose material from the work area.
Bond
(1) adhesion of concrete or mortar to reinforcement or other surfaces against which it is placed, including friction and mechanical interlock;
(2) adhesion of cement paste to aggregate;
(3) adhesion, cohesion, or both between materials;
(4) patterns for
Bond Area
the nominal area of interface between two elements across which adhesion, cohesion, or both, develop(s) or may develop, as between cement paste and aggregate.
Bond Plaster
a specially formulated gypsum plaster designed as first-coat applicationover monolithic concrete.
Bond Prevention
measures taken to prevent adhesion of concrete or mortar to surfaces against which it is placed.
Bond Strength
(1) resistance to separation of mortar and concrete from reinforcing and other materials with which it is in contact;
(2) a collective expression for forces such as adhesion, friction due to shrinkage, and longitudinal shear in the concrete engaged by th
Bond Stress
(1) the force of adhesion per unit area of contact between two bonded surfaces, such as concrete and reinforcing steel, or any other material, such as foundation rock;
(2) shear stress at the surface of a reinforcing bar, preventing relative movement bet
Boron-loaded Concrete
high density concrete including a boron-containing admixture or aggregate, such as the mineral colemanite, boron frits, or boron metal alloys, to act as a neutron attenuator. (See also biological shielding and shielding concrete.)
Bridge Deck
the structural concrete slab or other structure that is supported on the bridge superstructure and serves as the roadway or other traveled surface.
Briquette
a molded specimen of mortar with enlarged extremities and reduced center having a cross section of definite area, used for measurement of tensile strength (also called a briquet).
Broadcast
to toss granular material, such as sand, over a horizontal surface so that a thin, uniform layer is obtained.
Build-up
(1) spraying of shotcrete in successive layers to form a thicker mass;
(2) the accumulation of residual hardened concrete in a mixer.
Building Official
(1) the official charged with administration and enforcement of the applicable building code;
(2) the duly authorized representative of the official.
Bulk Cement
cement that is transported and delivered in bulk (usually in specially constructed vehicles) instead of in bags.
Bulk Density
the mass of a material per unit volume including voids between particles.
Bulkhead
(1) a partition in formwork blocking fresh concrete from a section of theform, or a partition closing a section of the form, such as at a construction joint;
(2) a partition in a storage tank or bin, as for cement or aggregate.
Bulking
increase in the volume occupied by a quantity of sand in a moist condition over the volume of the same quantity dry or completely inundated.
Bulking Factor
ratio of the volume of moist sand to the volume of the sand when dry.
Burlap
a coarse fabric of jute, hemp, or less commonly flax for use as a water-retaining covering in curing concrete surfaces (also called Hessian).