Glossary of Construction Terminology
ABRASION RESISTANCE: The ability of a concrete surface to withstand surface wear from machines and other materials.
ABRAM’S LAW: A rule stating that with given concrete materials and conditions of testing, the ratio of the amount of water to the amount of cement in the mixture design determines the strength of the concrete. ( Water to Cement Ratio )
ADMIXTURES: Materials and chemicals added to a concrete mix design which can increase strength, workability, lower freezing points, accelerate or decelerate setting time, entrain air or otherwise affect the placement, and curing of concrete.
Specifiers will dictate a “Mix Design” in the Job Specifications, which will include the water to cement ratio, the amount and type of aggregate as well as admixture portions to be added to the concrete mix. This “Mix Design” will vary according to the specific requirements of the slab or wall area to be poured.
- Accelerators: Chemicals, which increase the rate of hydration, shorten setting time as well as increase the rate of hardening and strength development.
These products are most often applied in cold weather applications.
- Aggregate: Inert materials, such as crushed limestone, sand, coral, and gravel, which serve as filler materials and can add significantly to the
compressive strength of concrete. The type of aggregate is normally dictated by the availability of natural resources and the function of
the slab or wall.
- Air Entraining Agents: Additives which cause the creation of minute air bubbles in the concrete mixture. This increases workability and frost resistance and allows for the expansion of the concrete without excessive cracking.
- Calcium Chloride: A chemical used to accelerate the hardening of concrete. The chemical is added to concrete mixtures during frost to accelerate
the rate of heat build up in the mixture, therefore increasing setting and hardening rates.
- Fly Ash: A substitute for cement, ( not to exceed 25% of the weight of the cement ) which reduces shrinkage and retards setting time, thus
Increasing working time.
- Micro Silica: ( Silica Fume ) A concrete additive, which drastically increases strength and reduces permability. It also makes the concrete
“ sticky “ and hard to finish. This additive is commonly used in Industrial floor applications where dry shake hardeners are not used.
- Plasticizers: Chemicals, which are used to increase the workability of concrete without decreasing strength. It helps to maintain a “plastic” state for extended periods without increasing the water content of the mixture.
- Retarders: Additives, which are used to delay the rate of hardening and setting of concrete. These products are most often used in hot weather pours to prevent the premature dehydration of the concrete.
- Water Reducers: Chemicals used to lower the water to cement ratio in the concrete mixture thus resulting in higher compressive strength.
BACKFILL: Earth or other material used to replace material removed during excavation in preparation for the construction of concrete walls, slabs,
culverts, pipelines, trenches or bridge abutments.
BATCH PLANT: An operating Installation with the equipment and materials required to mix and batch concrete Some plants are portable and are capable of installation on the job site.
BLEEDING: A term used to describe the rising of excessive water to the surface of a concrete slab. This is a normal process, which can be controlled by the addition of water reducers or other admixtures.
BONDING AGENTS: Chemicals used to insure the adhesion between newly poured concrete and existing substrates. These products are manufactured both in a two-part epoxy and a one part latex product. Epoxies are recommended for areas where adhesion could be difficult.
BUG HOLES: Holes left in the surface of formed concrete or grout, which reflect the location of aggregates, snap ties, or air products.
CAST IN PLACE CONCRETE: Concrete, which is poured in forms erected at it’s permanent location and allowed to harden and cure in this position.
CASSON: A foundation or support system whereby cavities are drilled in the earthen substrate and filled with concrete.
CEMENT: An ingredient in concrete, which is made by the burning of clay and crushed limestone.
CEMENT FACTOR: The number of bags or cubic feet of cement used in a cubic yard of concrete.
COLD JOINT: A stop in a pour, usually keyed, where newly poured concrete is placed adjacent to concrete which has set or begun to set.
COMPACTION: The density required on the surface, which concrete is to be poured. Compaction insures that the slab does not crack in areas where there is a soft under surface.
COMPRESSIVE STRENGTH: The measure of maximum resistance to load or weight. This factor is measured in “Pounds Per Square Inch” ( PSI )
CONCRETE CURING: The process of hydration, which allows the retention of moisture in a concrete mix to allow the attainment of maximum compressive strength. The prevailing specification for liquid membrane curing compounds is ASTM C-309. The following stipulations are required to meet this specification:
- The curing compound must form a membrane on the surface of the concrete, which will inhibit the evaporation of water through the concrete surface.
- The Solution must not allow the concrete to lose more than .55 kg. of water per square meter of area in 72 hours.
- Concrete Curing Methods:
- Liquid Membrane: Chemically sealing a slab to achieve C-309
- Types of Curing Compounds:
- Type 1: Clear or Transparent
- Type 1D: Clear with a fugitive dye
- Type 2: White Pigmented
- Classes of Curing Compounds:
- Class A: No restrictions on vehicle solids
- Class B: Vehicle Solids must be resin
- Types of Curing Compounds:
- Ponding: Curing with the continuous flow or accumulation of water on newly placed concrete.
- Waterproof Paper: The placement of a heavy bond Kraft paper that retains moisture without deteriorating.
- Burlap Curing: Water soaked burlap cloth ( Usually 9 oz per sq. yd. ) which maintains moisture on the concrete surface.
- Burlene: A curing blanket consisting of 5 mil opaque polyethylene and 10 oz. burlap. The opaque poly reflects sunlight and the burlap retains moisture.
CONCRETE JOINTS: Designed breaks or separations in a concrete pour designed to allow for expansion and contraction of the concrete and minimize or control cracking in a concrete pour.
- Types of Concrete Joints:
- Expansion Joints: A designed separation between newly poured concrete structures at critical intervals ( usually no more than 20 ft. apart ) intended
to allow for expansion and contraction in the concrete due to temperature changes. The absence of these joints will allow excessive cracking.
- Construction Joints: A joint formed by construction between two successive placements of concrete. Examples are column bases or pouring new slabs against existing concrete.
- Control Joints: A joint formed by sawing, tooling or grooving, which permits the uniform cracking of concrete. Joints must be sawed as soon as the concrete surface will support the weight of the machine used to saw the joints in order for the joints to be effective.
- Expansion Joints: A designed separation between newly poured concrete structures at critical intervals ( usually no more than 20 ft. apart ) intended
CUBIC MEASUREMENT: The measure of volume in cubic units is as follows:
1,720 Cubic Inches = 1 Cubic Foot
27 Cubic Feet = 1 Cubic Yard
Cubic Inches = 1 Gallon
128 Cubic Feet = 1 Cord
CURED CONCRETE: Concrete which has reached it’s maximum compressive strength.
CUM-A-LONG: A rake or tool used to move concrete around during placement.
CYLINDER TEST: A laboratory test which determines the compressive strength of an actual field sample of concrete which is usually 6 inches in diameter and 12 inches high in length. Samples are cured and then compressed in a hydraulic ram to measure the amount of pressure required to fracture the cylinder.
DEFLECTION: Any movement or variation from the intended grade line of the slab, beam or other structure.
DYNAMIC LOAD: A load or resistance, which is not static or stationary, such as the moving live load which exist in a earthquake or hurricane.
FINISH: The act of smoothing or impacting the desired texture on the surface of concrete. The texture or smoothness of a surface after finishing operations and screeding has been performed.
- Broom Finish: A rough textured finish on the surface usually created by the use of a stiff bristle broom.
- Hard Trowel Finish: A super smooth finish usually made by the use of mechanical finishing machines.
FLOAT: A tool, wooden or metallic, used in finishing operations to impart a relatively level surface.
FLOATING: The process of spreading plaster, stucco or concrete surfaces to a an equal thickness by the use of a wooden board or magnesium tool.
FLOATING SLAB: A special type of foundation made to carry the weight of a superstructure, which is to be erected on swampy or unstable soil.
FORMS: A temporary structure or mold for the support of concrete while it is setting and gaining sufficient strength to be self -supporting.
- Modular or Hand Set Forms: Smaller forms designed to be placed by hand. They are produced in various heights and lengths in order to be used in specific applications.
- Crane Set Forms ( Gang Forms ) : Larger forming systems which are used on mass pours and require the use of heavy lifting equipment to be placed in position.
- Slip Form: A form, which is pulled or raised as the concrete is placed. It generally moves horizontally to lay concrete evenly for highway pavement but can move vertically for concrete walls.
FOUNDATION: The entire substructure below the first floor frame of a building including the footings on which the structure rest.
FOOTING: The foundation for vertical walls or the area of the slab designed to support the weight of the roof and wall structures and transfer weight the weight of the building to the ground.
- Continuous Footing: Usually runs the perimeter and below weight bearing interior walls.
- Isolated Footing: Individual structures designed to support the weight of columns throughout the structure.
GRADE: The slope or ground level of a concrete slab, building or roadbed. Slab on grade is the slab poured on the ground level of the structure.
GRADE BEAM: A horizontal load bearing foundation member supported on each end like a standard beam. Not ground supported like a foundation wall or footing.
GRADING: Modification of the earthen or rock surface by cuts, fills or both. Normally done by mechanical equipment for gross work and shovel for more detailed work.
GREEN CONCRETE: Concrete which is in it’s earliest stage of curing and has not hardened appreciably. Typical pours take 28 days to cure.
HAUNCHING: The increased depth of a beam or slab near supports or footings to increase it’s strength and load bearing capability.
HEADWALL: A wall of any material at the end of a culvert or drain to serve one or more of the following purposes:
- Protect Fill from Scouring or undermining.
- Increase hydraulic efficiency by diverting water flow
- Serve as a retaining wall
HEAD PRESSURE: This term designates the capacity of a liquid circulator or the pressure at which a pump can induce the flow of a liquid. The rating is usually expressed in foot lbs. Of pressure
HIGH DENSITY CONCRETE: Concrete of exceptionally high unit weight, usually obtained by the use of heavyweight aggregates.
HIGH EARLY STRENGTH: Concrete which through the use of high early strength cement or admixtures, is capable of attaining a specified strength at an earlier age than normal concrete. It is frequently used when pours are made in low ambient temperatures.
HYDRAULIC CEMENT: A type of cement or mortar which is capable of hardening under water.
INTRAGAL WATERPROOFING: A term for waterproofing concrete by including a waterproofing admixture In the mix design.
JETTING: A method of sinking piles with the use of high pressure water or air jets. This method is used very commonly in marine applications where pile-driving machinery is not practical.
KEYWAY: A recess built into a lift or placement of concrete, which is filled with the concrete from the next pour, giving shear strength to the joint. This joint is usually formed with 10’ metal strips and stakes.
KRAFT PAPER: A type of strong, water resistant brown paper, which can be used in several construction applications, the most frequent of which is a curing paper for freshly poured slabs.
LASER LEVEL: An electronic devise which uses a laser light beam to define and exhibit the specified grade level.
LASER SCREED: An electronic, self-propelled machine which moves concrete to the specified grade through the use of laser light beams as well as self-contained floating and finishing equipment.
LIGHTWEIGHT CONCRETE: A mixture with substantially lower unit weight and compressive strength than concrete made with crushed rock or stone aggregate. Normally used on upper floor levels or roof tops where weight is a factor.
LOAD BEARING WALL: Any wall, which bears it’s own weight as well as the weight of a ceiling or roof. A wall built to withstand wind resistance.
MODULUS: A unit of measure used in describing the strength of a material.
MODULUS OF ELASTICITY: The unit of measurement or ratio of normal stress to corresponding strain under movement.
MONOLITHIC CONCRETE: Concrete cast with no joints other than construction joints. A slab poured in a continuous uninterrupted manner.
MUDSLAB: A two to six inch slab below a structural concrete floor or footing over soft or wet soil.
NON-SLIP FLOOR:A concrete floor surface which has been roughened by treatment with iron or synthetic filings, carborundum powder or the placement of indentions in the surface while the surface is still wet.
NO-SLUMP CONCRETE: Concrete with a slump of one inch or less.
PAN AND BEAM FORMING: A prefabricated form in a pan shape, used in conjunction with concrete floor joist. Used most commonly for slab pourings on multi-story structures.
PARAPET: A protective railing or low wall around and along a roof’s edge line.
PEA GRAVEL: Screened gravel, which most particles will pass through a 3/8” screen.
PLACING DRAWINGS: Detail sheets, usually provided by reinforcing steel fabricators, to aid in the correct installation of reinforcement steel.
PLASTICITY: The measurement of a substance’s ability to remain in a plastic or workable state. ( The ability to be deformed or shaped ) An index of
PILE: ( PILING ) A long timber, concrete or steel structure jetted or driven into the ground for the purpose of supporting building foundations.
PILE CAP:A structural member placed on and usually attached to the top of a piling or group of pilings and used to transmit loads to the piling or group of pilings. It can be constructed of poured concrete, timber or steel beams.
POLYMER CONCRETE: A concrete created from the use of synthetic materials as opposed to normal Portland cements. Polymers allow a much smoother finish as well provide strength.
Type 1: Standard Portland cement. A general purpose cement for a variety of construction applications.
Type II: A modification of Type 1, which is resistant to Sulphate attacts and a decreased rate of heat evolution.
Type III: A high early strength and quick hardening cement.
Type IV: Designed for a low heat hydration.
Type V: Designed for extreme Sulphate resistance.
POST-TENSIONED CONCRETE: A method of stressing reinforced concrete in which tendons or cables are tightened after the concrete slab is hardened and put in place.
PRE-CAST CONCRETE: Concrete, which is cast and cured in a location other than it’s final resting Positon and transported to it’s final position. ( pre-cast beams, Lintels, wall panels and elevated slabs )
PRE-STRESSED CONCRETE: A process of preparing concrete slabs and beams for extra strength by pouring concrete mix over tightly drawn steel cables, steel rods or tendons to provide strong dense concrete.
READY MIXED CONCRETE: Concrete manufactured for delivery according to specific mix designs to a purchaser in a plastic and unhardened state.
REINFORCED CONCRETE:Concrete with added materials such as rebar, wire mesh, fiber mesh, dowel bars, expanded metal fabric or cold drawn wire cable, which act together with the concrete to resist external force.
RETAINING WALL: A wall built to prevent dirt, rock or other matter from eroding on to construction areas.
RUBBED FINISH: A finish obtained by application of Portland Cement, sand and water or other cementitious compounds to fill bug holes or other deformities on a
Freshly poured concrete surface.
RUBBLE CONCRETE: Concrete made from rubble and concrete debris from demolished surfaces.
SCARIFYING: Disruption of the smooth surface of concrete by creating scars, dents and a generally rough surface to remove any chemical bond inhibitors and permit the acceptance of bonding, sealing, adhesive or other coating materials.
SCREED: a. The process of leveling or finishing the surface of a concrete slab. This can be accomplished by hand as well as sophisticated machinery. b. a tool or machine used to level a concrete surface.
SCREED PIPE: A round steel pipe, usually 1” in diameter, used to identify the grade level of freshly poured concrete. The pipe is used as a straight edge and pulled along the surface of the concrete.
SET: The condition reached by concrete, mortar or cement when it has lost it’s plasticity to the degree that it stiffens and begins the hardening process.
SHOP DRAWINGS: Incidental drawings furnished by reinforcement suppliers and equipment manufactures that conform to the original architectural and structural drawings. They illustrate how specific portions of a project blend and work in sequence. They also give specific installation instructions.
SHOTCRETE: Mortar, concrete or other cementitous materials conveyed by air pressure through a hose at high velocity onto a surface for stabilization, water and debris control.
SHRINKAGE: A decrease in volume and mass caused by temperature and chemical changes in concrete, mortar and grout during the curing process. It can be controlled with admixtures.
SLAB ON GRADE: A non-suspended, ground supported concrete slab, usually reinforced, on the lowest or primary level of a project.
SLUMP: The measure of the consistency of concrete rated in terms of inches. A mixture with a 3” slump will have less flow ability than a mixture with a 9” slump. Higher slumps are required when pouring walls to insure that the concrete penetrates to the bottom of the form and completely surrounds the reinforcement steel. High slumps are also required when pumping is required. Higher slumps are achieved by the addition of admixtures, which increase flow ability without decreasing strength. The slump is measured by the use of a slump cone.
SLUMP CONE: A cone shaped mold with a base diameter of 8 inches and a top diameter of 4 inches and a height of 12 inches. A sampling of concrete mixture is placed in the cone and the measure of slump is measured by the decrease in the height of the sample statue once the cone is removed from the sample.
STRENGTH: The measure of a material’s ability to resist load or stress.
SUBGRADE: The uppermost material of a substrate on which concrete or asphalt is to be placed. The foundation for pavement or asphalt structures.
SUBSTRATE: The base or lower surface on which a substance is to be applied. An earthen substrate is the normal substrate for poured in place concrete.
TRANSIT: An Instrument commonly used by surveyors for identifying levels an measurements for project lay outs.
TROWELING: The smoothing and compacting of the uniformed surface of freshly poured concrete.
TROWELING MACHINE: A motor driven device, which operates orbiting steel blades on radial arms from a vertical shaft for the purpose of smoothing and compacting freshly poured concrete.
ULTIMATE STRENGTH: The maximum resistance to load that a structure is capable of developing before failure occurs.
VIBRATION: The use of a mechanical device to facilitate the consolidation of concrete in deep pours or pours with a very low slump.
VIBRATOR: An electric, hydraulic or gasoline powered tool used to insure consolidation of concrete during a deep pour in a wall or slab. It consist of a power source, usually an electric motor, a “whip” on variable length shaft, and a head on the end of the shaft opposite of the motor, which vibrates and causes concrete to move down and around reinforcement. Wall mounted models, which attach directly to the side of metal forms are also available.