In addition to the concrete mix and the weather conditions, concrete’s hardness and the type of cutting equipment are also important factors in determining when to saw concrete. By cutting too early, one causes raveling, an effect caused by the saw blade pulling the aggregate out of place, leaving a messy, weakened edge. The saw blade is also subjected to undue wear. As the concrete contracts during curing, too late sawing can result in uncontrolled cracking.
When the weather is hot, saw cutting may begin as soon as four hours after the concrete is poured. It may take up to 12 hours after pouring to start sawing in cooler weather. Making trial cuts to check for raveling is the best way to determine whether the slab is ready. During these trial cuts, saw cutting should begin as soon as raveling stops.
By delaying sawing, contractors protect their equipment and reduce blade abrasion. Based on the concrete type and how soon the cuts can be made, there are several types of saw blades that can be used. Additional factors that can contribute to excessive blade wear and joint raveling are:
- Too much pressure on the blade
- causes the saw to cut at high speeds
- When using a saw with a bent spindle
- an inappropriate blade is used