Posted on: 6 July 2016Share
Concrete sawing is a vital part of the concrete installation process, as it ensures that freshly poured concrete is able to cure properly. Unfortunately, the practice of concrete sawing is still largely misunderstood--especially by those with jobs in the construction sector. If you would like to improve your knowledge of this important phase of concrete installation, this article will present three important things to know about sawing concrete.
Sawing concrete prevents the formation of shrinkage cracks.
As concrete dries, a certain proportion of its water content evaporates into the air. This evaporation causes the surface of the concrete to undergo a measurable dimension change. In other words, the concrete shrinks. This shrinkage places a large deal of stress on the surface of the concrete, often causing it to pull apart from itself, thus forming what are known as shrinkage cracks.
The primary purpose of sawing concrete is to keep these unsightly cracks from forming. It does this by creating stress-relieving joints. These achieve the same result as the shrinkage cracks would—relieving the surface tension of the drying concrete. Unlike cracks, however, they do it while maintaining a regular, consistent appearance.
The timing of a cut determines its success.
Unless joints are cut in the concrete at just the right time, they may end up doing more harm than good. If the cuts are made before the concrete has cured for long enough, so-called joint raveling may ensue. This problem is characterized by joints whose edges have a ragged, deteriorated appearance. They may also continue to degrade and crumble as time goes on.
Putting off the concrete sawing too long may also lead to unanticipated problems. That's because if the concrete is allowed to harden for too long, the sawing tends to disrupt the drying process. This often leads to cracking in the areas immediately adjacent to the joint.
Concrete sawing should take place between 4 and 12 hours after the concrete has been poured. In general, cold or especially moist conditions mean the concrete will need to cure for longer. Hot, dry weather, on the other hand, will promote quicker drying, meaning that the joints will need to be cut at the earlier end of this spectrum.
Depth must be closely regulated for a cut to be effective.
Even those who time their concrete sawing just perfectly may not end up with the intended results. This is often the result of joints that are too shallow. Fortunately, you can avoid this scenario by keeping a simple rubric in mind. A concrete joint should always be 25 percent as deep as the concrete is thick.