The words “cement” and “concrete” are solidly (pun intended) engrained in our language and culture. Both are different, as suggested by some interesting quotes.
Consider this one offered by Oliver Sacks, a British Neurologist: “Music has bonding power, it is primal social cement.” Or this one from R. G. LeTourneau, American Inventor: “The pebbles of knowledge must be bonded together by the cement of experience.” And this one by Geneen Roth, American Author: “Chocolate, I am sure, is the concrete manifestation of love.”
Notwithstanding the actual difference between the two words, most Americans get them confused. For example, it is common to call the large trucks on construction sites with the big rolling barrels on their backs “cement mixers” when, in reality, they are “concrete mixers.”
What Is Cement?
Cement is a binding agent, and almost all cement used in the world is called “portland cement” (even though it doesn’t come from Portland, OR). Portland cement comes from elements found in limestone, including aluminum, calcium, and silica. Lime and silica make up about 85 percent of cement. Other ingredients in cement usually include clay and silica, or silica sand.
In some regions of the country, cement mixtures can consist of small amounts of iron oxide, iron ore, gypsum, fly ash, or shale. The components of the cement “formula” are super-heated, thus creating a hard rock-like substance that is ground into an extremely fine powder.
Portland cement is a conventional grey color due to the iron or manganese in it. There is also white portland cement made from the same ingredients but without the iron or manganese.
What Is Concrete?
Making concrete requires the blending of cement, aggregate, and water. Thus, those big trucks with rolling barrels keep the mixture well-mixed and fluid. When combined with water and aggregate, the cement hardens and binds through a chemical reaction called hydration.
Concrete is much more durable than cement itself. Concrete is used for large projects, while cement is used for smaller jobs, including minor repairs. The adhesive properties of cement make it an excellent binding agent, but the aggregates added in the concrete blending process make concrete substantially stronger than cement. Cement, on its own, is prone to cracking.
Types of Cement
There are various types of portland cement, each formulated to address different physical and chemical requirements including:
- Type 1 — a general-purpose cement.
- Type 2 — used for structures built in soil containing moderate amounts of sulfate.
- Type 2 (MH) — created to be moderately sulfate resistant.
- Type 3 — made to achieve early strength, typically in a week or less.
- Type 4 — used for massive concrete structures like a dam that needs to moderate the heat generated by hydration in the construction process.
- Type 5 — manufactured to resist chemical attacks in high sulfate water and soil conditions.
Components of Concrete
In addition to the water blended with cement, concrete uses a variety of aggregates, either in a mixture or as a selection of one of these, including large aggregates like gravel or crushed stone, a small aggregate like pea gravel, or a fine aggregate like sand.
Aggregates make up about 75 percent of the concrete mixture. Cement comprises 10 to 15 percent of the mix, and water completes the formula. The water and other ingredients must be clean because any organic material contamination will compromise the concrete’s strength.
Where Is Concrete Used?
Concrete is the solid and reliable construction material used worldwide in roads, sidewalks, backyard patios, bridges, and dams. Concrete is used to build structures that support buildings and walls. To contrast the two, at home, concrete would be used to pour a patio, and cement would be used to set posts for a fence.
The Advantages of Concrete
Because of its strength and durability, concrete is used extensively as a building material. Consider the foundations of most homes, the cores of today’s skyscrapers, the thousands of miles of sidewalks in our cities and towns, and the great spans of drainage culverts under our city streets.
Concrete is almost universally available.
Concrete is a versatile substance. Construction workers can pour concrete into any shape needed on a job site without cutting or bending it. Builders and architects use concrete to offer strength, safety, and energy efficiency.
Architects are now using insulated concrete forms for building homes because concrete is not vulnerable to termites, rot, fire, and moisture damage as wood-framed homes are. Also, houses built with these concrete-filled forms are becoming more popular in coastal areas where they are more hurricane-resistant.
Good concrete is resistant to freezing, thawing, deicing chemicals, and wear. It is also watertight.
Some Other Things to Know about Concrete
An optimized concrete mix design is the function of five components: strength, durability, density, workability, and appearance. Workability refers to the ability of a construction team to put the concrete into place, especially if it must be pumped into position. Appearance can be a factor in many applications, but it is also a critical factor in decorative applications.
A key determinant of concrete strength is the ratio of cement and water in the mixture. The higher the composition of water, the weaker the concrete will be.
Protecting concrete surfaces from deterioration from aggressive materials like acids can be achieved by using a lower water-to-cement ratio, selecting a more resistant cement type, and choosing from various protective sealings and coatings.
Decorative finishes can be applied to concrete surfaces by adding pigments before or after the concrete is in place, utilizing chemical stains, or applying colorful aggregates to the surface of the concrete after it is poured. Additionally, textured finishes and patterns can be scored, stamped, inlaid, or rolled into the concrete.
What Can McConnell & Associates Do for You?
For just about every surface under your feet, McConnell & Associates can help you. Since 1965, McConnell & Associates has restored, beautified, and protected surfaces throughout the Midwest. That includes restoring and repairing concrete sidewalks, curbs, and gutters, resurfacing tennis courts, installing new running tracks, and protecting paved and sports surfaces.
McConnell & Associates is the regional expert in preventative maintenance, including asphalt installation, maintenance and repair, seal coating, crack filling, patching, paving, striping, and markings. We also do concrete repair, curb & gutters, concrete sealing, and speed bumps.
We can install and maintain everything from a backyard tennis court to a complete athletic complex for a school or community center.
Contact McConnell & Associates with offices in Kansas City, St. Louis, Pevely, and Wichita. McConnel now leads the industry with premium pavement, concrete, and sports surface products and services. We offer the depth of experience to make your project a success.