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a concrete surface crack with a width so small as to be barely perceptible.
(1) the wedge used to tighten some types of form ties; (2) a hairpin-shaped anchor set in place before concrete reaches initial setting; (3) a lighthairpin-shaped reinforcing bar used for shear reinforcement in beams, tie reinforcement in columns, or pr
(1) flared shotcrete nozzle having a larger diameter at midpoint than ateither inlet or outlet; (2) designated premixing tip.
concrete that has developed sufficient strength to serve a defined purposeor resist stipulated loading without failure.
(1) a chemical (including certain fluosilicates or sodium silicate) applied to concrete floors to reduce wear and dusting; (2) in a two-component adhesive or coating, the chemical component that causes the resin component to cure.
gain of strength and other properties of a cementitious mixture as a resultof hydration after final setting.
a concrete mixture that lacks desired workability due to a deficiency of mortar or aggregate fines.
a deepened portion of a beam in the vicinity of a support.
a tool used by plasterers to hold and carry plaster mortar; generally a flat piece of wood or metal approximately 10 to 12 in. (0.25 to 0.3 m) square with a wooden handle centered and fixed to the underside. (See also hod and mortar board.)
a separate piece of steel of any shape firmly attached to the end of a bar or a protuberance of the bar itself at the end, used to anchor a steel reinforcing bar in concrete.
the maximum force that can be transmitted from the head of the bar to the surrounding concrete.
area of the head projected onto a plane orthogonal to the longitudinal axis of the bar minus the bar cross sectional area, representing the contact surface between head and concrete where the bar tensile force is transferred through compression stress.
a steel reinforcing bar that has steel head(s) on one or both ends with the purpose of anchoring the bar in concrete.
a masonry unit laid flat with its greatest dimension at a right angle to the face of the wall (when the unit is only the depth of the face wythe, it is known as a false header). (See also bonder and wythe [leaf].)
(1) heat evolved by chemical reactions with water; (2) the difference between the heat of solution of dry cement and that of partially hydrated cement. (See also heat of solution.)
a method in which a liquid or suspension of given specific gravity is used to separate particles into a portion lighter than (those that float) and a portion heavier than (those that sink) the medium.
aggregate of high density, such as barite, magnetite, hematite, limonite, ilmenite, iron, or steel, used in heavyweight concrete.
a mineral, iron oxide (Fe 2 O 3 ), used as aggregate in high-density concreteand in finely divided form as a red pigment in colored concrete.
(1) a hydrate containing one-half molecule of water to one molecule of compound; (2) partially dehydrated gypsum (also known as plaster of paris), CaSO 4 – 1/2H 2 O. (See also bassanite and plaster of paris.)
concrete of substantially higher density than that made using normal- density aggregates, usually obtained by use of high-density aggregates and used especially for radiation shielding.
portland cement characterized by attaining a given level of strength in mortar or concrete earlier than does normal portland cement (referred to as ASTM C150 Type III).
concrete that, through the use of additional cement, high-early-strength cement, or admixtures, has accelerated early-age strength development.
a hydraulic cement of substantially higher specific surface and substantially smaller mean particle diameter than typical for products of similar composition produced by additional grinding or by separation by particle size.
concrete meeting special combinations of performance and uniformity requirements that cannot always be achieved routinely using conventional constituents and normal mixing, placing, and curing practices.
a water-reducing admixture capable of producing large water reduction or great flowability without causing undue set retardation or entrainment of air in mortar or concrete.
concrete that has a specified compressive strength for design of 8000 psi(55 MPa) or greater.
steel with a high yield point (in the case of reinforcing bars 60,000 psi[414 MPa] and greater). (See also prestressing steel.)
voids left in concrete between coarse aggregates due to inadequate consolidation.
a bend in the end of a reinforcing bar.
the law, for strains within the elastic limit, that the strain is proportional to the stress producing it. (See also elastic limit and proportional.)
a reinforcing bar with the end bent into a hook to provide anchorage.
a closed or continuously wound tie, each having hooks meeting seismic detailing requirements.
metal or wood load-carrying strut, beam, or trussed section used to carry a shoring load from one bearing point, column, frame, post, or wall to another (may be adjustable).
a mixer having a stationary cylindrical mixing compartment, with the axis of the cylinder horizontal and one or more rotating horizontal shafts to which mixing blades or paddle are attached (also called a pugmill).
newly manufactured cement that has not had an opportunity to cool after grinding of the clinker.
the surface of a refractory section exposed to the source of heat.
a test for determining the resistance to deformation or shear of a refractory material when subjected to a specified compressive load at a specified temperature for a specified time.
radial expansion of the prestress material due to its Poisson coefficientcaused by the release of pretension.
a chemical combination of water with another compound or an element.
calcium hydroxide, a dry powder obtained by treating quicklime with water.
the chemical reaction between hydraulic cement and water.
a binding material that sets and hardens by chemical reaction with water and is capable of doing so underwater. For example, portland cement and slag cement are hydraulic cements.
the hydrated dry cementitious product obtained by calcining a limestone containing silica and alumina to a temperature short of incipient fusion so as to form sufficient free calcium oxide to permit hydration and at the same time leaving unhydrated suffic
a grout that is a mixture of hydraulic cement, aggregate, water, and possibly admixtures.
a shotcrete hose and nozzle configuration used in place of a predampening system to introduce pressurized water into the material stream via a water ring.
