The Glossary of Concrete Terms

There's always more to learn, especially about concrete. Here are some common terms used in the concrete industry that could help you understand more about concrete and the industry behind it.

1. Abrams' law 
The rule of concrete that says, under many conditions using common concrete materials, concrete strength is inversely related to the ratio of water to cement. This means low water-to-cement ratios tend to produce higher concrete strengths.

2. Admixture
Commonly applied to affect air entrainment, curing time, and plasticity, admixtures are substances used sparingly to modify the results of a mix or final concrete product. Admixtures are materials other than water, aggregate, and cement (the basic components of concrete). 

3. Aggregate
Aggregate, a mixture of sand, rock, crushed stone, expanded materials, or particles, both enhances the structural performance of concrete and improves cement paste’s formation and flow. Aggregate usually constitutes about 75% of concrete volume.  

4. Air-entraining
Air-entrained concrete contains minute air bubbles that are distributed uniformly throughout the cement paste.  Entrained air can be produced in concrete by use of an air-entraining cement, by introduction of air-entraining admixture, or by a combination of both methods.  Air-entraining admixtures are used to stabalize microscopic air bubbles in concrete.  Proper air-entrainment, with appropriate volume and spacing factor, will dramatically improve the durability of concrete exposed to moisture during cycles of freezing and thawing.  Entrained air also improves concrete's resistance to surface scaling causes by chemicals deicers.  

5. American Concrete Institute (ACI)
An international organization providing education and information about concrete.

6. American National Standards Institute (ANSI)
The United States representative in the International Organization for Standardization (ISO).

7. American Standard of Testing Materials (ASTM)
An organization that serves as a standardized testing center to evaluate the performance of a variety of building materials. 

8. Apron
A slab of concrete, often at an entrance for vehicles, that extends beyond a building’s entrance.  

9. Bleeding
The self-generated release of mixing water from freshly placed concrete. 

10. 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.

11. Concrete
Concrete is not the same as cement. Concrete is a combination of cement as a binding agent, chemical additives, water and mineral. This combination, when properly mixed and placed, hardens into an excellent building material for a wide variety of uses. 

12. Control joint
Usually straight saw cuts made on concrete surfaces. These lines form the boundaries or “joints” where the concrete can relieve tension as it cures. 

13. Curing
Curing ensures that concrete will set to its design strength under favorable conditions, usually after 28 days. Curing is the hardening of concrete through the controlled evaporation of water or a solvent, hydration, polymerization, or chemical reactions of various types. Successful concrete curing requires the maintenance of satisfactory temperature and moisture content. 

14. Dampproofing and waterproofing
Processes or chemicals used on concrete that prevent the coated surface from absorbing water while still permitting moisture vapor to escape from the structure. Generally speaking, "dampproofing" applies to above grade surfaces while "waterproofing" refers to below grade surfaces. 

15. Dry shake (dry topping)
A concrete surface treatment where a dry material is shaken onto the surface to produce color, hardening, or antiskid results. The dry shake is applied before the concrete sets, and is then troweled in. 

16. Drying shrinkage
Concrete surface contraction caused by the loss of moisture. 

17. Finishing
The treatment (compacting, leveling, smoothing, etc.) of recently placed or fresh concrete to ensure the planned-for surface. 

18. Flatwork
Mostly flat-surfaced concrete work, including sidewalks, driveways, basements and concrete floors. 

19. Grade 
A building site’s (or building’s) existing or proposed ground level or elevation. Also used in categorizing building or construction levels, e.g. above grade, on grade, or below grade. 

20. Hydration
The chemical reaction, often indicated by an increase in temperature, that results when water and cement are mixed.

21. Placing
The physical introduction of the concrete mixture into the final location where it is to harden and cure. 

22. Plasticity 
The characteristic determining the resistance to deformation or ease of molding in cement paste, freshly mixed concrete, or mortar. 

23. Portland cement
Cement made by heating a limestone and clay mixture in a kiln and pulverizing the resulting material. Concrete made with portland cement is believed to be more consistent and stronger than concrete made from natural cement.

24. Scaling 
The breaking away of a concrete surface. Contrast to spalling, the flaking or chipping of concrete.

25. Slump
A measurement of concrete's workability.  Slump is a test for the rigidity of uncured concrete.  Lower slump concrete is very stiff, and higher slump concrete is more fluid.  It's an indirect measurement of concrete's quality. 

26. Slump Test
The slump cone is a right circular cone that is 12 inches high.  The base of the cone is 8 inches in diameter and the top of the cone is 4 inches in diameter.  The cone is filled with fresh concrete in three layers of equal volume.  Each layer is stroked 25 times with a rod, the end of which is bullet shaped.  After the cone has been filled with concrete and the concrete has been cut off with the top of the cone, the cone is raised vertically allowing the concrete to fall or slump.  The distance that the concrete falls or slumps from the original height is the slump of the concrete.  Slump is measured in inches and is reported to the nearest inch.

27. Spalling
Spalling is 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.

28. Troweling
The use of a trowel (a flat steel tool that manipulates concrete) to smooth and compact the surface of fresh concrete. 

29. Water repellant coating
Concrete surface treatment, usually a transparent coating or sealer, that repels water when applied.