Definitions of Concrete Terms

Admixture – A material other than cement, aggregates and water added as an ingredient in concrete. Examples: Air entrainment, water-reducing admixtures and fly ash.

Aggregate – Natural or crushed stone and sand which is a main component of concrete. The natural gravel and/or crushed limestone serve as coarse aggregates; the natural river sands serve as fine aggregates.

Air Entrainment – The incorporation of air bubbles in concrete to improve workability or to improve durability to freezing and thawing conditions.

Bleeding – Water in the concrete rising to the surface of fresh concrete, caused by settling of solid material.

Blowup – A condition that occurs when concrete sets up too fast, or a flash set.

Booster Load Truck – A long wheelbase truck with a lifting rear axle.

Calcium Chloride – An admixture used to accelerate the setting of concrete; may contribute to rusting of reinforcing steel and may contribute to the discoloration of flatwork surfaces.

Cement – The ingredient in concrete that slowly reacts chemically with the water to form the bonding agent that holds the aggregate together.

Chute – A sloping trough on a concrete mixer truck, through which concrete moves from the truck to a form or receptacle. Chutes for the concrete mixer truck consist of the main chute and a fold-over chute, then three add-on chutes (each 4 feet long), for a total chute length of sixteen feet.

Compressive Strength (PSI)- Pounds Per Square Inch, which indicates strength of concrete.

Concrete – A composite material made of Portland cement or other hydraulic cement, aggregate, water, and sometimes admixtures, which hardens when the cement reacts chemically with water.

Control Joint – A joint designed to accommodate movements in concrete inevitably caused by temperature changes and drying shrinkage. Made by forming, tooling, or sawing a grove in a concrete structure, this creates a weakened plane that will cause cracking to occur along this predetermined line instead of at random locations. Also referred to as a contraction joint.

Curing – Maintenance of satisfactory moisture content and temperature in concrete during its early stages so that desired properties may develop.

Curing Compound – A liquid that can be applied as a coating to the surface of newly placed concrete to retard the loss of water, or in the case of pigmented compounds, also to reflect heat, thus providing an opportunity for the concrete to develop its properties in a favorable temperature and moist environment.

“C” Gravel – A size of gravel used in standard concrete mixes.

Demurrage – A charge for the time spent waiting, which is in excess of the time allowed, to unload a truck.

Durability – The ability of concrete to maintain its integrity and form under harsh conditions.

Efflorescence – A deposit of salts on the surface which has emerged from within the concrete and been deposited by evaporation.

Expansive Soil – Soil subject to considerable volume increase, causing uplift of concrete structures.

Exposed Concrete – A finishing process in which the sand and cement are removed from the surface, exposing the aggregate.

Finishing – The process by which the desired smoothness, density, and flatness are applied to the concrete; usually floating and/or troweling are used.

Finish Sand – Sand, which is lignite free, used for smooth steel trowel finishing. In our area, sand from the Meramec River is preferred

Flatwork – A general term referring to driveways, patios, floors, and other projects consisting of a flat slab.

Flowable Fill—A non-concrete material that is low strength and may be easily removed. It is designed for protection around utility lines. Depending on the use, the product may be low slumped or very high slumped.

Fly Ash—A fine residue resulting from burning of powdered coal, used as an admixture to react with cement and enhance properties of concrete.

Foundation – A concrete wall supporting a structure.

Glacial Gravel – Multi-colored gravel that was deposited by glaciers. In this area it is used for exposed aggregate finish.

Grade – The surface on which a slab of concrete is placed; or, to prepare a surface on which to place a slab of concrete.

Gravel – Material found around riverbeds, which is cleaned and sized.

Grout – A mixture of cement and/or fly ash, water and sand, properly proportioned.

Honeycomb – Voids left in concrete where cement and sand particles have not filled the spaces among the coarse aggregate particles.

Isolation joint – A structural separation between adjoining elements of a concrete structure, with the purpose of preventing cracks caused by movements of the individual parts.

Lien waiver – A document signed by a supplier proving that payment has been received for specified materials provided at a specified time.

Material Safety Data Sheet –Information including product identification and chemical data, recommended safety precautions while using the product, handling and disposal methods, etc. For our ready mix concrete, this is printed on the back of every delivery ticket. For other products, these are available upon request.

Lignite – A black lightweight material found in the sand from the Mississippi and Missouri Rivers, that will float to the top of the concrete surface; therefore, concrete containing it is not aesthetically pleasing.

Meramec Sand – Sand from the Meramec River that is free of lignite, and is used as finish sand, as opposed to River Sand (from the Mississippi and Missouri Rivers) that does contain lignite.

Mid-Range Water Reducer – A concrete admixture that will enhance the performance of concrete in both the plastic and hardened states.

Micro Fiber – A very fine fiber added to concrete to reduce cracking.

Old Monroe Torpedo – A multi-colored 3/8” gravel from the Old Monroe Deposit, located in Old Monroe, Missouri. In this area it is used for exposed aggregate finish.

Plastic Shrinkage – The shortening of the surface of fresh concrete caused by the rapid evaporation of moisture due to low humidity, high winds, high temperature, or a combination that often leads to cracks occurring before the concrete has been finished.

Popout – A small piece of concrete that has separated from the structure due to internal pressure, leaving a small gap, which is sometimes referred to as “chert.”

Portland Cement - A hydraulic cement that conforms, both in composition and properties, to the requirements of ASTM Standard C150.

PSI – An abbreviation for “pounds per square inch.” The strength of concrete is expressed in PSI at 28 days.

River Sand – Sand containing lignite, processed from the Mississippi and Missouri Rivers. It is used for roads and structural concrete.

Ready Mix Concrete – Concrete that has been batched at a concrete plant and is mixed in a mixer truck with the proper proportions of water and admixtures and delivered to the jobsite ready for placement.

Rock – Broken pieces of stone that are removed from quarries.

Scaling – Flaking, chipping, or peeling away of the surface of hardened concrete.

Stone – Limestone aggregate processed in quarries.

Sealer – A liquid composition applied to the concrete surface to lessen the

absorption of water or other liquids.

Slab – A horizontal surface of concrete used as pavement, floor, roof, patio, or wall.

Slump – A measure of consistency and stiffness of concrete. The higher the slump, the more fluid the concrete.

Spalling – The breaking away of a small piece or chunk of concrete, usually by expansion from within the larger mass.

Stamp Concrete – A concrete finish in which imprinted mats are placed on the surface, causing the texture to be stamped into the concrete. This requires a special concrete mix.

Superplasticizer – A high range water reducer which when added to low slump concrete will increase the slump of the concrete without being detrimental to the strength.

Torpedo – A 3/8” Meramec gravel.

Troweling – Smoothing and compacting the surface of a concrete slab by using strokes of a trowel.

Will Call – A given time at which a customer will call to confirm an order that is on hold until such time that the customer calls to request a delivery time.

Wire Mesh – A mesh made of wires crossing at right angles and welded together, used as reinforcement in concrete.

Workability – The ease with which concrete can be mixed, placed, compacted, and finished.

Zip Strip – A brand name of a plastic T- shaped material used as a control joint, whereas the top of the T strip is removed after placement.