How to Keep Concrete From Getting Plastic Shrinkage Cracks

Completely compact the area in which you will be pouring the concrete. Go over the surface several times with a compaction machine. Between each run, check with a level to assure that your sub-grade stays level.

Lightly spray the sub-grade with water from a garden hose to keep it from leaching the moisture from your concrete.

Place a layer of fine gravel or sand on top of your sub-grade. This will act as a cushion and help buffer any settling that may occur.

Insert wire mesh or re-bar in the formed area before you pour the concrete. This helps stabilize the structure as a whole, giving the concrete something to adhere to within.

Order cement that has fiber-mesh in it. These are tiny nylon fibers that are added directly to the cement mix. They act much like the steel mesh but on a microscopic level, helping to keep the cracks to a minimum.

Protect the freshly poured concrete from direct sunlight by suspending the tarp over the concrete surface. Pound 4 aluminum poles at least 6 inches into the ground with the hammer at the corners of the concrete. Secure the tarp by threading the rope through the eyelets and tying each corner tightly to a pole.

Protect the freshly poured concrete from wind by creating a wind-block using the tarp. Pound 2 of the aluminum poles at least 6 inches into the ground on one side of the concrete (depending on the direction from which the wind is blowing). The width between the poles should be the same as the width of the tarp you will be using. Secure the tarp by threading the rope through the eyelets and tying the top corners to the top of the poles and the bottom corners to the bottom of the poles so that it is stretched between the two poles creating a windbreak.

Form contraction joints in the wet cement. Place them every 8 to 10 feet along the length of your surface by drawing the jointing trowel from one side to the other of the cement while it is still wet. The depth of these joints should be about 1/4 inch.