The Science Behind Concrete
In one form or another, concrete has been in use for 12,000 years and is often found in early archeological excavations in the cradle of civilization. It has shaped construction throughout the ages. Now it’s shaping design too.
The Romans developed new techniques with cement that allowed them to construct buildings that we still admire today. They found that a mix of lime, sand, and crushed rock produced a substance that worked very well as an adhesive in their masonry buildings.
In the 1800s, many advances were made in the understanding of how specific ingredients influenced cement. John Smeaton found that it was the clay content in limestone that made cement harden when combined with water. A mason named Joseph Aspdin of Leeds discovered Portland cement around the same time. It is a mix of silica sand, clay, limestone, and shells crushed together and combined with other elements then heated thousands of degrees before it is ground into powder. Portland cement is a type of hydraulic cement, which means that it begins to set up and harden when mixed with water.
Today, advances with cement and concrete abound. Chemical knowledge has allowed for the development of specialty products with varying degrees of strength, durability, resistance, and workability. That means that whatever the project, there’s a unique blend of concrete that’s formulated specifically for that.
Let’s Get Technical
Concrete is just one form of construction materials made with cement. Cement is a binder used in things like concrete, mortar, and other adhesives. It’s what holds everything together.
There are over 20 types of concrete for everything from runways to decorative goods, with often ingenious attributes. There’s concrete that senses flaws so structure failure can be detected before a disaster. There’s concrete filled with microscopic air bubbles to make it more able to withstand freezing temperatures. There’s concrete that’s resistant to radiation. The list goes on.
Developments in concrete are happening all the time. Within the decorative concrete category, there are various types of mixes to choose from. Some are made specifically for countertops, while others are designed for products that are near works of art. Decorative concrete can be colored, molded, polished, etched, and textured for an aesthetic appeal.
Each of these concrete blends employ high-tech components in different amounts to achieve mixes perfectly suited to specific results. Here’s a closer look.
Fibers in concrete give it better resistance to shattering, abrasion, and impact. There’s a lot of math and engineering that goes into fiber-reinforced concrete so it can have the right elasticity, binding ability, flexural strength, tensile strength, and overall toughness.
For decorative concrete, glass or polyester fibers are the most commonly used. Steel fibers are used in construction concrete and often replace the need for rebar.
Polymers are large chemical structures made of chains of repeating smaller units, and acrylic is a type of plastic. The addition of acrylic polymers to concrete mixes makes the finished product more adhesive, gives it greater flexural and tensile strength, and better freeze/thaw durability.
What does this mean for your concrete dining table? It means that you can sit in the middle of it and won’t break. It means that it can undergo force pushing or pulling on it and it will remain strong.
Plasticizers are a high-tech chemical compound that reduce the amount of water needed to produce concrete. That means the mixture isn’t as heavy. They also decrease the viscosity of the mixture resulting in better workability.
For your decorative concrete, plasticizers allow for the making of some very artistic shapes. It also helps in the making of large tables since it doesn’t weigh as much.
When concrete is mixed with water, an exothermic reaction takes place which raises the temperature and causes the mix to expand. When concrete begins to cool and dry, it shrinks. A shrinkage reducer uses dextrins and hydroxylated carboxylic acids that increases the expansion of concrete as it cools. It expands at about the same rate as contraction occurs - effectively stopping stress on the concrete. That in turn reduces cracking related to shrinkage.
Other chemicals and pigments are added to the mix or applied after pouring to produce artistic effects like finishes, stencils, textures, and color. Concrete products are available in many different aesthetics suitable for interior decorating and design.
For instance, you can custom order any Benjamin Moore paint color in concrete. You can have your business’s logo etched onto any number of concrete products. Standard products at Trueform include beautiful mottled finishes that rival natural stone for the countertop or wall. Or select the smooth Classic Finish in eight colors.
The science behind concrete today is what makes it such a versatile material capable of creating just about anything you can dream up. Want some ideas? Take a look at these beautiful finished spaces.