Tips for laying concrete slabs
Before starting to lay concrete slabs ensure that you have removed all vegetation, soft soils, and rocks so that support for the slab is clear and even. If possible, use a surface with undisturbed, firm soil.
It is advisable to use set-forms to ensure that the concrete slab surface slopes a minimum of two percent.
The use of a scratch template, typically, a piece of 40x40mm or 40x80mm wooden beam or one equal to the specified slab thickness with stakes attached to the top surface at each end, or a string line across the top of the forms to ensure proper slab thickness.
Strike off the surface while keeping a small amount of concrete in front of the straightedge to fill in low spots. This helps to prevent depressions in the finished surface.Bullfloat or darby the surface before the concrete begins to bleed.
Do not perform any finishing operation while bleed water is present on the surface. Do not dust dry cement on the surface to soak up bleed water.
Use a groover to make contraction joints in the fresh concrete. Make sure the groove depth is a minimum of 25% of the slab thickness. As an option, saw the joints using either an early-cut saw or a conventional saw. Early jointing helps prevent cracking.
Start curing the concrete immediately after completion of finishing operations.