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Concrete Ideas, pt. 1

© John J. Pascarella

Working with concrete is something most of us will experience at one time or another when we work on our homes. It may be something as simple as a sidewalk or as complicated as footings for a foundation wall. But what exactly is "concrete"?

Key Concrete Ingredients
Concrete contains three basic ingredients: cement, aggregate and water. Cement, or portland cement, is the glue that holds everything together; a fine, dry powder that solidifies and becomes quite strong when mixed with water. The majority of concrete is the aggregate. Aggregate is a mixture of clean sand and gravel. It must be clean for the cement to bind to it and it must contain enough fine material (sand and small gravel) to fill the spaces between the larger pieces of gravel. The final ingredient is water. The water combines with the cement in a chemical process called hydration. What this means is that the cement begins to form crystals between the pieces of aggregate, resulting in a strong, solid rock-like material. The key to good quality concrete is the right amount of water. Too much water will result in weak concrete. Most concrete mixtures are a ratio of 1 to 2, or 1 part water to 2 parts dry materials.

Additional Concrete Ingredients
Sometimes concrete contains other ingredients, or admixtures. In cold climates, air entrainment is the most common. Air entrainment is a fancy way to say that there are microscopic air bubbles in the finished, hard concrete. These air bubbles help the concrete withstand the freezing and thawing that would otherwise ruin the surface of the concrete. There are other admixtures that are used for extremely hot weather, delaying finishing time or to prevent the concrete from freezing before it has a chance to cure.

In upcoming articles, we will look at estimating how much concrete you will need, tips to mix your own concrete, terms you will need to know when ordering concrete, and working with concrete. Until next time, In Bocca Al Lupo!

The copyright of the article Concrete Ideas, pt. 1 in Home Renovation is owned by John J. Pascarella. Permission to republish Concrete Ideas, pt. 1 in print or online must be granted by the author in writing.