Accelerator
Chemical substance added to a concrete mix that reduces the set time by increasing the rate of hydration.
Acid Stain
Also known as chemical stain. A stain containing inorganic salts dissolved in an acidic, water-based solution that reacts chemically with the minerals in hardened concrete to produce permanent, transparent color that will not peel or flake. Gives concrete an attractive variegated or marbleized appearance. Colors tend to be earth tones, such as tans, browns, reddish browns, and greens.
Acrylic Sealer
A water-based sealer that forms a protective film on the surface of the concrete that imparts a sheen that highlights the beauty of regular and decorative concrete.
Adhesion
The sticking together of substances that are in contact with one another.
Admixtures
All materials, other than Portland cement, water, and aggregates, that are added to concrete, mortar, or grout immediately before or during mixing.
Aggregate
Bulk materials, such as sand, gravel, crushed stone, slag, pumice, and scoria, that are used in making concrete.
Air Content
The amount of entrained or entrapped air in concrete, usually expressed as a percentage of total volume.
Anchor Bolts
Any of a variety of rather large J- or L-shaped bolts designed to have a portion embedded in concrete or mortar.
Ashlars
A squared or rectangular block of building stones in the ashlar pattern.
B
Backfilling
The process of piling earth against the outer surface of a form.
Base Coat
Each of the lower layers of plaster, if more than one coat is applied.
Batter Boards
A board frame supported by stakes set back from the corners of a structure that allows for relocating certain points after excavation. Saw kerfs in the boards indicate the location of the edges of the footings and the structure being built.
Bed Joint
The horizontal layer of mortar on which a masonry unit is laid.
Bleed Water (Bleeding)
Water that rises to the surface of freshly placed concrete due to segregation. Bleeding may interfere with finishing operations.
Block
A concrete masonry unit made with fine aggregate and cement that is shaped in a mold. Any of a variety of shaped light-weight or standard weight masonry units.
Bond
The property of a hardened mortar that knits the masonry units together; also the lapping of brick in a wall.
Brick Masonry
A type of construction that has units of baked clay or shale of uniform size, small enough to be placed with one hand, laid in courses with mortar joints to form walls of virtually unlimited length and height.
Brick Set
A wide-blade chisel used for cutting bricks and concrete blocks.
Broom Finish
Surface texture obtained by pushing a broom over freshly placed concrete.
Brown Coat
Second coat of plaster or stucco in three-coat work.
Buttered
The small end of a brick that has quantity or mortar placed onto it (e.g., the act of buttering a brick's end with mortar).
C
Cast in place
Concrete placed and finished in its final location.
Caulk
To seal up crevices with some flexible material.
Cement
Cement is not the same as concrete, but rather one component of concrete. Cement, a combination of finely ground materials, hardens when mixed with water to become the "glue" in concrete.
Closure Brick
A partial brick that is cut to fit into place to complete a course
Coloring Agents
Colored aggregates or mineral oxides ground finer than cement.
Compressive Strength
Maximum resistance that a concrete, mortar or grout specimen will sustain when loaded axially in compression in a testing machine at a specified rate; usually expressed as force per unit of cross sectional area, such as pounds per square inch (PSI).
Concrete
An artificial stone made by mixing cement and sand with gravel, broken stone, or other aggregate. These materials must be mixed with sufficient water to cause the cement to set and bind the entire mass.
Control (Horizontal) Joints
Sawed or tooled groove in a concrete slab used to regulate the location of cracking.
Control Joints
Continuous vertical joints built into concrete walls to control cracking resulting from unusual stresses. Control joints are intended to permit slight wall movement without cracking.
Coping
A brick, block, stone, or concrete cap placed at the top of a masonry wall to prevent moisture from falling directly on it and weakening the wall.
Corbeling
Courses of bricks set out beyond the face of a wall in order to form a self-supporting projection.
Courses
One of the continuous horizontal layers (rows) of masonry that form the masonry structure.
Curing
The process of protecting concrete against loss of moisture during the earliest stage of setting.
D
Darby
A longer version of a hand float, ranging in length from 2 to 4 feet. Useful for leveling problem areas.
Decorative Concrete
Concrete that has been enhanced by color, pattern, texture, or a combination of ornamental treatments.
Degreaser
A chemical solution for removing grease, oils, and other contaminants from concrete surfaces.
Delamination
A separation of a coating or topping from a substrate or the layers of a coating from each other due to poor adhesion. Or in the case of a concrete slab, a horizontal splitting or separation of the upper surface.
Dry Mixture
Mixture of concrete whose water content is severely restricted.
Drying Shrinkage
A decrease in the volume of concrete as it dries, due to loss of moisture. See also plastic shrinkage cracks.
E
Edger
A concrete finishing tool for rounding the edge of freshly poured concrete; one of several finishing techniques.
Edging
The process of rounding the edge of freshly poured concrete; one of several finishing techniques.
Efflorescence
A powdery stain, usually white, on the surface of or between masonry units. It is caused by the leaching of soluble salts to the surface.
Expansion Joint
A material placed within or a scoring of concrete that allows it to expand without cracking.
Exposed Aggregate
A concrete finish achieved by embedding aggregate into the surface, allowing the concrete to set up somewhat, then hosing down and brushing away the concrete covering the top portion of the aggregate.
F
Face Brick
A type of brick made specifically for covering (veneering) walls.
Feather Edge
To smoothly, seamlessly blend the edge of a topping or repair material into the existing concrete.
Finish Coat
The top layer of plaster if the plaster is applied in more than one coat.
Finishing
Leveling, smoothing, compacting, and otherwise treating the surface of newly placed concrete or concrete overlays to produce the desired appearance and service properties.
Flashing
The waterproofing covering placed to set up certain points in brick masonry to hold water or to direct any moisture outside the wall.
Float
A wooden tool used to finish a concrete surface.
Footing
A base for a wall or structure that provides stability for that structure.
Form
A parameter or set of parameters made from earth or wood and, on occasion, steel, that contains the footage concrete.
Frost Line
The maximum depth to which frost normally penetrates the soil during the winter. This depth varies from area to area depending on the climate.
Furrowing
Striking a V-shaped trough in a bed of mortar.
G
Gradation
The distribution of particle sizes, from coarse to fine, in a given sample of fine coarse aggregate.
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.
Groover
A tool with a V-shaped bit used to create control joints in plastic concrete.
Grout
A water-cement, or water-cement-sand mixture, used to plug holes or cracks in concrete, seal joints, fill spaces between machinery bed plates and concrete foundations, and for similar plugging or sealing purposes.
H
Hard-troweled Finish
Surface finish obtained by using a trowel with a steel blade for final finishing of concrete. Often used where a smooth, hard, flat surface is desired.
Hawk
A fairly small board with a handle beneath it used for holding mortar.
Header
A masonry unit laid flat with its longest dimensions perpendicular to the face of the wall. It is generally used to tie two wythes of masonry together.
Hydration
The chemical reaction that occurs when water is added to cement, causing it to harden.
I
Integral Color
A coloring agent premixed into fresh concrete or cementitious toppings before placement.
Isolation Joint
Isolation (or expansion) joints separate or isolate slabs from other parts of the structure such as walls, footings, or columns; and driveways and patios from sidewalks, garage slabs, stairs, light-poles and other points of restraint. They permit independent vertical and horizontal movement between adjoining parts of the structure and help minimize cracking when such movements are restrained.
J
Joint
Any place where two or more edges or surfaces come to a union.
Jointer
A tool used for making grooves or control joints in concrete surfaces to control cracking. (See Control Joint)
Joist
In deck construction, 2" x 6" lumber attached to beams and ledgers that serves as a base for the deck planking.
K
L
Laitance
A thin layer of fine, loosely bonded particles on the surface of fresh concrete, caused by the upward movement of water. Laitance must be removed before application of a decorative coating or topping.
Lintel
A beam placed over an opening in a wall.
M
Margin Trowel
A steel trowel with a small, rectangular flat blade about 5 to 8 inches in length and a short handle. It has multiple uses, including scraping off concrete from finishing tools and applying patching materials.
Masonry
A construction made of prefabricated masonry units laid in various ways and joined together with mortar.
Material Safety Data Sheet (MSDS)
Information sheets containing pertinent chemical ingredients, product handling and safety guidelines.
Mixers
Vehicles or containers used to blend or mix the ingredients of concrete.
Moisture Content
The amount of water contained within the aggregate used in concrete.
Mortar
A mixture of cement, sand, and water without coarse aggregate. It is used chiefly for bonding masonry units together.
N
O
P
Pavers
Bricks in numerous sizes and shapes that are used in constructing sidewalks, patios, and driveways.
Penetrating Sealer
A sealer with the ability to penetrate into the concrete surface to increase water repellency. Penetrating sealers chemically react with the concrete preventing water and salt penetrating down through the concrete.
Permeability
The degree to which a membrane or coating will allow the passage or penetration of a liquid or gas.
Pier
A free-standing column.
Pilaster
A projection from a masonry wall that provides strength for the wall.
Plastic
A condition of freshly mixed concrete indicating that it is workable and readily moldable.
Plastic Shrinkage Cracks
Irregular cracks that occur in the surface of fresh concrete soon after it is placed and while it is still plastic.
Plasticity Consistency
A sluggish flow without segregation.
Plumb
That which is vertically perpendicular as measured with a spirit level or plumb bob.
Pointing
The process of inserting mortar into horizontal and vertical joints after a masonry unit is laid.
Portland Cement
A number of types of cement with unique characteristics manufactured from limestone and mixed with shale, clay, or marl.
Precast Concrete
Any concrete member that is cast in forms at a place other than its final position of use.
Pre-Mix
Any of several packaged mixtures of ingredients used for preparing concrete or mortar.
Q
R
Reinforcing Rod
A steel rod that is used for reinforcing concrete and masonry structures.
Retaining Wall
A wall that is constructed to hold soil in place.
Rowlock
A brick laid on its edge (face).
Rubble
Rough fragments of broken stone either naturally formed or quarried; used in masonry.
Running Bond
This is the same as common bond, with continuous horizontal joints, but the vertical joints are offset or in line.
S
Scratch Coat
The first coat of plaster or stucco.
Screed
A long, very straight board used for striking off concrete.
Screeding
The process of leveling the surface of a concrete slab by striking off the excess concrete.
Segregation
The tendency of particles of the same size in a given mass of aggregate to gather together whenever the material is being loaded, transported, or otherwise disturbed.
Set
The condition reached by concrete when plasticity is lost, usually measured in terms of resistance to penetration or deformation. Initial set refers to concrete that has reached first stiffening. Final set occurs when concrete attains full rigidity.
Shell
The sides and recessed ends of a concrete block.
Shotcrete
Mortar or small-aggregate concrete that is conveyed by compressed air through a hose and applied at high velocity to a surface. Also known as gunite and sprayed concrete.
Slump
A measure of consistency of freshly mixed concrete, as determined by the distance the concrete slumps after a molded specimen is removed from an inverted funnel-shaped cone.
Soldier
A brick laid on its ends so that its longest dimension is parallel to the vertical axis of the face of the wall.
Spalling
Damage caused by water entering concrete and forcing the surface to peel, pop out, or flake off. Concrete spalling is most likely to occur on exterior surfaces that are exposed to freeze and thaw cycles. Causes include
high water cement ratio in the concrete mix, lack of air entrainment, improper finishing, and inadequate curing.
Stretcher
A masonry unit laid flat with its longest dimension parallel to the face of the wall.
Striking Off
The process of removing excess concrete to a level needed.
Stucco
A finish composed of two or more layers of mortar (white or colored) that is applied to either indoor or outdoor walls.
T
Tamp
The process of compacting concrete with rakes or short lengths of lumber.
Technical Data Sheet
Contains important specifications and guidelines for product usage. Includes such data as coverage rates, recommended applications, product limitations, surface preparation guidelines, mix ratios and required mixing times, pot life, application procedures, cure times, performance data, and precautions.
Texturizing
Creating a particular finish, such as brushed, smoothed, etched, or pockmarked.
Ties
A wire, rod, or snap that is used to hold wall forms at a specific separation.
Trowel
A flat, broad-bladed steel hand tool used to compact the paste layer at the surface and provide a smooth, flat finish.
Tuck-Pointing
The process of refilling old joints with new mortar.
U
V
Veneer
A layer of bricks or stones that serves as a facing.
W
Wales
Horizontal members that aid in wall/form reinforcement and distribution of forces.
Water-cement Ratio
The ratio of the amount of water to the amount of cement in a concrete mixture.
Weep Holes
The openings made in mortar joints that facilitate drainage of built-up moisture.
Wire Mesh
Any of a variety of types of bonded wire forming a mat used to reinforce slabs of concrete.
Workability
The ease or difficulty of placing and consolidating concrete.
Working Time
The amount of time available for placing and finishing a cement-based material before it begins to set. Often depends on the ambient temperature and substrate temperature.
Wythe
A vertical stack of bricks one thickness wide (e.g., a veneer course).
