Concrete is made up of three relatively simple ingredients: aggregate, cement, and water. Yet that doesn't make installing concrete a simple task. Contractors must account for a multitude of different factors in order to ensure optimal results, both in terms of appearance and long-term structural stability.
One of the most important aspects of concrete installation is compacting the concrete. Compaction occurs soon after the concrete has been poured into the forms that define its ultimate shape. If you would like to learn more about the process of compaction, and its critical role in concrete installation, keep reading. This article outlines three key goals of concrete compaction.
1. Reduce Entrapped Air Levels
Virtually all freshly poured concrete contains unintended pockets of entrapped air. Some of this air has existed inside the concrete since the mixing process. Yet more air becomes entrapped in the concrete during the process of placing it inside of its forms. The concrete often folds over itself as it is being poured, causing pockets of air to become trapped inside of it.
The difference between entrained air and entrapped air is important. Entrained air consists of small, evenly dispersed air bubbles. These bubbles tend to benefit concrete by creating space for the volume increase associated with freezing water during periods of cold weather.
Entrapped air, on the other hand, almost always has a detrimental effect on the concrete. The considerably larger voids associated with entrapped air reduce the durability and strength of the concrete.Entrapped air pockets that develop along the walls of forms will also negatively affect the appearance of the concrete.
During the process of compaction, workers agitate the poured concrete using one or more types of vibrators. These vibrations cause the aggregate particles in the concrete to rearrange themselves into tighter configurations, pushing pockets of entrapped air up toward the surface in the process. Compaction creates a uniform interior and thus increases long-term strength.
2. Increase Bond With Reinforcing Agents
Pockets of entrapped air will form naturally as workers pour concrete into even the most basic of forms. Yet the problem tends to grow worse for concrete structures that feature internal reinforcing agents such as rebar or steel mesh. As concrete hits the top of these elements and falls into place, larger pockets of entrapped air form around the reinforcing agents.
Not only does such entrapped air create the same problems discussed above, but also it greatly negates the intended benefits of the reinforcing agents. In order to increase the overall stability of the slab, those reinforcements must be as thoroughly surrounded by concrete as possible. Compacting ensures that the concrete forms a thorough bond with any and all reinforcing agents.
3. Ensure Fine Surface Finish
When installing things like driveways and floors, contractors achieve a smooth finish by leveling and floating the poured concrete. In that case, creating an even finish tends to be relatively easy because workers have direct access to the surface. Finishing becomes much more challenging, however, on vertical surfaces.
A worker has no way to smooth or level the side of a concrete wall because the wall will remain protected by its form until fully cured. Any entrapped air between the concrete and its vertical form will ultimately give the wall a rough and stubbly appearance. In some cases, such an appearance might be acceptable.
When creating interior concrete walls, builders tend to prefer a smooth, fine finish. Compacting the fresh concrete helps to push it against the form as uniformly as possible, removing any air bubbles that would negatively affect its appearance.
Compaction has a huge role to play in concrete installation. To ensure a smooth finish on your next concrete installation project, contact the experts at Jimenez Concrete Inc.