3 Most Frequently Asked Concrete Questions11 Jan 2016, Posted by Concrete Facts in
Concrete is all around us. We work, live and play in buildings made of it and drive over bridges molded from it. We’ve developed expertly engineered forming products that allow us to craft elaborate concrete structures faster than ever before.
Concrete is everywhere we look, but how much do we really know about it? We’ve gathered the 3 most commonly asked questions about concrete in order to gain a better understanding about this wonderful substance.
What Is the Difference Between Concrete and Cement?
The simplest answer to this question is that cement is actually one of the materials that makes up concrete. Essentially, cement is a powder made of limestone that binds all of the other ingredients in concrete together.
The modern words for both cement and concrete have Latin origins. Concrete comes from the word “concretus,” meaning to harden together. Cement comes from the word “caementum,” meaning roughly cut stone.
Pavement is extremely similar to concrete, but with one small difference. In pavement, the cement binder is replaced with asphalt or tar.
What Are the most Common Types of Concrete?
Concrete has become the most commonly used structural substance in the world due to its versatility. Different additions to the mix add different beneficial properties, and as a result, there are many different types of concrete. However, there are four types that can be considered the most common.
Accelerators have been added to this type of concrete to reduce setting time. The amount of reduction in setting time varies depending on the amount of accelerator used.
This type of concrete is often used in hot weather conditions to delay setting time. It is also used to delay setting time for more difficult jobs or for special finishing operations like exposing aggregate. Many retarders also act as a water reducer.
Air Entraining Admixtures
This type of concrete must be used whenever the structure will be exposed to freezing and thawing and de-icing salts. Air entraining agents entrains microscopic air bubbles in the concrete: when the hardened concrete freezes, the frozen water inside the concrete expands into these air bubbles, preventing damage to the concrete.
Water Reducing Admixture
In this type of concrete, the amount of water needed in the concrete mix is reduced. Because the water cement ratio will be lower, the strength will be greater. Most low range water reducers reduce the water needed in the mix by 5%-10%. High range water reducers reduce the mix water needed by 12% to 30% but are very expensive.
How Long Does Concrete Last?
Concrete can last for thousands of years. In fact, the oldest known man-made concrete mix dates back to around 500 BC. However, many factors such as environmental humidity, maintenance and aggregate quality can greatly affect the lifespan of concrete.
So there you have it, answers to the three most commonly asked questions about concrete. Now you know a little more about this often-overlooked substance that makes up our world.