Concrete Waterproofing Glossary

D-cracking

a series of cracks in concrete near and roughly parallel to joints and edges resulting from use of coarse aggregate that is susceptible to damage during cycles of freezing and thawing.

treatment of concrete or mortar to retard the passage or absorption ofwater or water vapor either by application of a suitable coating to exposed surfaces, or by use of a suitable admixture or treated cement, or by useof a preformed film such as polyethyl

Darby

a hand-manipulated straightedge, usually 3 to 8 ft (1 to 2.5 m) long, used in the early stage leveling operations of concrete or plaster, preceding supplemental floating and finishing.

Dash-bond Coat

a thick slurry of portland cement, sand, and water flicked on surfaces with a paddle or brush to provide a base for subsequent portland cement plaster coats, sometimes used as a final finish on plaster.

Dead End

in the stressing of a tendon from one end only, the end opposite that to which the load is applied.

Dead Load

(1) the weights of the structural members, supported structure, and permanent attachments or accessories that are likely to be present on a structure in service;
(2) loads meeting specific criteria found in the governing building code (without load facto

Dead-end Anchorage

the anchorage at that end of a tendon that is opposite the jacking end.

Debonding

(1) preventing bond of prestressing tendons to surrounding concrete;
(2) bond failure at the interface between a substrate and a strengthening or repair system.

Deck

the form on which concrete for a slab is placed, also the floor or roof slabitself. (See also bridge deck.)

Decking

sheathing material for a deck or slab form.

Decorative Concrete

concrete that has received treatments to create aesthetic effects. These treatments may include coloring, polishing, texturing, embossing, molding, etching, applying cementitious toppings, embedding items, or a combination of these.

Deflection

movement of a point on a structure or structural element, usually measured as a linear displacement or as succession displacements transverse to a reference line or axis.

Deformation

a change in dimension or shape. (See also expansion, creep, length change, volume change, shrinkage, and time-dependent deformation.)

Deformed Bar

a reinforcing bar with a manufactured pattern of surface ridges intended to reduce slip and increase pullout resistance of bars embedded in concrete.

Deformed Reinforcement

metal bars, wire, or reinforcement with a manufactured pattern of surface ridges that provide a locking anchorage with surrounding concrete.

Dehydration

removal of chemically bound, adsorbed, or absorbed water from a material.

Deicer

a chemical, such as sodium or calcium chloride, used to melt ice or snow on slabs and pavements; such melting being due to depression of the freezing point.

Delamination

a planar separation in a material that is roughly parallel to the surface of the material.

Delay

see presteaming period.

Delayed Ettringite Formation

a form of sulfate attack by which mature hardened concrete is damaged by internal expansion during exposure to cyclic wetting and dryingin service and caused by the late formation of ettringite, not because of excessive sulfate; not likely to occur unless

Delivery Hose

hose through which shotcrete, grout, or pumped concrete or mortar passes(also called conveying hose or material hose).

Demold

to remove molds from concrete test specimens or precast products. (See also strip.)

Dense-graded Aggregate

aggregates graded to produce low void content and maximum density when compacted. (See also well-graded aggregate.)

Density

mass per unit volume.

Density (dry)

the mass per unit volume of a dry substance at a stated temperature.

Density Control

control of density of concrete in field construction to ensure that specifiedvalues as determined by standard tests are obtained.

Design Load

applicable loads and forces or their related internal moments and forces used to proportion members.

Design Strength

nominal strength multiplied by a strength reduction factor f . (See alsonominal strength and phi factor).

Deterioration

(1) physical manifestation of failure of a material (for example, cracking, delamination, flaking, pitting, scaling, spalling, and staining) caused by environmental or internal autogenous influences on rock and hardened concrete as well as other materials

Development Bond Stress

see anchorage bond stress (preferred term).

Development Length

the bonded length required to achieve the design strength of a reinforcement at a critical section.

Diagonal Crack

(1) in a flexural member, an inclined crack caused by shear stress, usually at approximately 45 degrees to the axis;
(2) a crack in a slab, not parallel to either the lateral or longitudinal directions.

Diagonal Cracking

development of diagonal cracks. (See also diagonal tension.)

Diagonal Tension

the principal tensile stress resulting from the combination of normal and shear stresses acting upon a structural element.

Dicalcium Silicate

a compound having the composition 2CaO – SiO 2 , abbreviated C 2 S, an impure form of which occurs in portland-cement clinker (belite). (See also belite. )

Differential Thermal Analysis (DTA)

indication of thermal reaction by differential thermocouple recordingof temperature changes in a sample under investigation compared with those of a thermally passive control sample, both of which are subjected simultaneously to the same heating condition

Dilation

an expansion of concrete during cooling or freezing generally calculated as the maximum deviation from the normal thermal contraction predicted from the length change/temperature curve or length change/time curve established at temperatures before initial

Direct Dumping

discharge of concrete directly into place from crane bucket or mixer.

Discoloration

departure of color from that which is normal or desired.

Disintegration

reduction into small fragments and subsequently into particles. (See alsodeterioration and weathering.)

Dispersing Agent

a material capable of increasing the fluidity of pastes, mortars, or concretesby reduction of inter-particle attraction.

Distribution-bar Reinforcement

small diameter bars, usually at right angles to the main reinforcement, intended to spread a concentrated load on a slab and to prevent cracking.

Dome

square prefabricated pan form used in two-way (waffle) concrete joist floor construction.

Dormant Crack

a crack whose width does not change with time.

Double-tee Beam

a precast-concrete member composed of two stems and a combined topflange, commonly used as a beam but also used vertically in exterior walls.

Dowel

(1) a steel pin, commonly a plain or coated round steel bar that extends into adjoining portions of a concrete construction, as at an expansion or contraction joint in a pavement slab, so as to transfer shear loads;
(2) a deformed reinforcing bar intende

Dowel Rod

see dowel ( preferred term).

Drainage Fill

(1) base course of granular material placed between floor slab and subgrade to impede capillary rise of moisture;
(2) lightweight concrete placed on floors or roofs to promote drainage.

Draped Tendons

tendons that have a trajectory that is curved or bent with respect to the gravity axis of the concrete member.

Drier

chemical that promotes oxidation or drying of a paint or adhesive.

Drilled Pier

a concrete pier with or without a casing, cast in place in a hole previouslybored in soil or rock. (See also cast-in-place pile.)

Drilled-in Caisson

cast-in-place pile formed by driving an open-ended steel pipe into bedrock or other bearing layer, cleaning out the pipe, drilling a socket into the bedrock or other bearing layer, and placing the steel reinforcement and concrete (also called caisson foun

Drip

a transverse groove in the underside of a projecting piece of wood, stone,or concrete to prevent water from flowing back to a wall.

Drop Panel

the thickened structural portion of a flat slab in the area surroundingcolumn, column capital, or bracket to reduce the intensity of stresses.

Dry Mix

(1) a concrete, mortar, or plaster mixture, commonly sold in bags, containing all components except water;
(2) a concrete of near-zero slump.

Dry Mixing

blending of the solid materials for mortar or concrete before adding the mixing water.

Dry Pack

concrete or mortar mixtures deposited and consolidated by dry packing.

Dry Packing

placing of zero-slump, or near zero-slump, concrete, mortar, or grout byramming into a confined space.

Dry Process

in the manufacture of cement, the process in which the raw materials are ground, conveyed, blended, and stored in a dry condition. (See also wet process.)

Dry Rodding

in measurement of the mass per unit volume of coarse aggregates, the process of consolidating dry material in a calibrated container by rodding under standardized conditions.

Dry-batch Weight

the mass of the materials, excluding water, used to make a batch of concrete.

Dry-cast Process

a process for producing concrete products, such as pipe, usinglow-frequency high-amplitude vibration to consolidate dry-mix concrete in the form. (See also centrifugal process, packerhead process, tamp process, and wet-cast process.)

Dry-mix Shotcrete

shotcrete in which most of the mixing water is added at the nozzle (also called dry-process shotcrete).

Dry-packed Concrete

concrete placed by dry packing.

Dry-rodded Density

mass per unit volume of dry aggregate, which includes the volume of the particles and the voids between particles, compacted by rodding under standardized conditions.

Dry-rodded Volume

the bulk volume occupied by a dry aggregate compacted by rodding under standardized conditions; used in measuring density of aggregate.

Dry-rodded Weight

(deprecated term) see dry-rodded density.

Dry-shake

a dry mixture of hydraulic cement and fine aggregate (either mineral or metallic) that is distributed evenly over the surface of concrete flatwork and worked into the surface before time of final setting and then floated and troweled to desired finish.

Drying Shrinkage

shrinkage resulting from loss of moisture.

Dunagan Analysis

(obsolete) a method of separating the ingredients of freshly mixedconcrete or mortar to determine the proportions of the mixture.

Durability

the ability of a material to resist weathering action, chemical attack, abrasion, and other conditions of service.

Durability Factor

(1) a measure of the change in a material property over a period of time as a response to exposure to a treatment that can cause deterioration, usually expressed as percentage of the value of the property before exposure;
(2) in ASTM C666/C666M, a measure