Getting Back to Basics: How Fresh Concrete Is Made
Concrete is one of the most versatile materials used in construction. It is used to build homes, office buildings, roads, bridges, patios, sidewalks, parking lots, and more. One of the reasons concrete is so widely used is because it is strong and durable once it fully hardens and cures.
Another reason concrete is the perfect choice for such a wide range of projects is that it is environmentally friendly. Concrete is made from naturally occurring materials and is 100% recyclable. Now that you understand the benefits of using fresh concrete, let’s find out how it’s made.
Are Cement and Concrete the Same Things?
Many people use the terms cement and concrete to mean the same thing. For example, they might say they have a cement driveway instead of a concrete driveway. However, while the terms are used interchangeably, they are entirely different.
What Is Concrete?
Concrete is a mixture of three different components in different mix ratios:
- Paste (Cement)
It is essential to get the mix ratios correct to ensure the paste can properly bind the aggregates together and allow them to harden into durable and strong concrete.
What Is Cement?
Cement is a combination of various materials, such as clay, aluminum calcium, iron, limestone, and silicon. These materials are mixed and heated to form a rock-like substance, which is then ground into a fine powder. This fine powder is used as the “paste” part of concrete to help bind it together.
What Are Aggregates?
Aggregates are various naturally occurring materials that allow us to make cement. Aggregates include sand, pebbles, small rocks, ground-up seashells, coarse gravel, and recycled cement. There are two different types of aggregates:
- Fine Aggregates – Fine aggregates consist of materials that are 0.2 inches or smaller in size.
- Coarse Aggregates – Coarse aggregates are any materials that are larger than 0.2 inches but smaller than 1.5 inches.
Concrete can consist of a mixture of both fine and coarse aggregates.
The Proportioning Process
Mixing concrete is frequently referred to as the proportioning process. Proportioning involves determining what percentage of cement, aggregates, and water are the perfect mix ratio. For example, if your mix ratio had too much cement, it would result in a very smooth finish, yet it would not be as strong and could crack, chip, and break.
On the other hand, if you mixed in too many aggregates, the result would be coarse concrete with a rough finish that was porous. As a result, the concrete would absorb water and deteriorate much faster.
Adding too much water to the mix ratio would result in runny concrete that is hard to shape. As the water evaporates and it hardens, it also shrinks. It is also highly prone to cracking because it is not as strong as properly mixed concrete.
So, to make high-quality, durable, and strong concrete, you need to be skilled at knowing what mix ratio to use and how to adjust the quantities of cement, aggregates, and water to achieve this. Furthermore, one of the most essential aspects of mixing concrete is understanding the ratios between water and cement.
Ideally, to achieve the best results, you want to divide the weight of water by the weight of the cement. In addition, lowering the water-to-cement ratio is one of the most commonly used options to increase the quality of the concrete.
What Is the Ideal Mix Ratio of Concrete?
There are different percentages used to calculate the ideal mix ratio. Most importantly, you want to ensure the aggregates used fit with the type of project. For example, if you want thin concrete, you want to use more coarse aggregates than fine aggregates.
Next, water quality is vital when determining the mix ratio. You want to use regular drinking water. You want to avoid using reclaimed water, as it could still have some impurities that would affect the end result and quality of the concrete.
Keeping these things in mind, your mix ratio should be:
- 14 to 20% Water
- 8 to 15% Cement
- 60 to 75% Aggregates
The exact science of mixing fresh concrete to obtain the highest quality of results also depends on knowledge, experience, and years of trial and error to determine the proper mix ratio.
What Is the Hydration Process?
This is a chemical reaction that occurs when water is added to the cement and aggregates. The reaction allows the cement to become paste-like and bind with the aggregates. After binding with the aggregates, the chemical reaction continues, causing the concrete to harden and become solid, strong, and durable.
It is important to pour the concrete as soon as it is well mixed and the hydration process has started. After the slurry is poured, you need to work with it quickly to remove air pockets and smooth it out.
Curing begins from exposure to the air and allows dehydration to begin. It is vital the concrete continues to harden, so it becomes durable and strong. Last, after dehydration is complete, it needs to be sealed to preserve it and ensure it lasts a long time.
Quality Concrete in Houston
Now that you understand the science behind mixing fresh concrete, you can see why getting the right mix ratio and high-quality results can be challenging. So when you want the highest quality of concrete for your residential or commercial project in the greater Houston area, please feel free to contact Cross Construction Services at 713-254-1703 today!