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Mix and Pour Cement...
What You'll Need
- cement mixer (if you're mixing cement yourself)
- wheel barrow
- screed (long enough to span opposite form boards)
- tamper
- bullfloat
- power cement finisher (for a very large slab)
- concrete finishing trowels
What You Do
Mixing Cement
If you're pouring a large concrete slab, you'll most likely want transit-mix cement which is delivered in barrel trucks. For smaller jobs, or ones that allow you to pour manageable areas in stages, you can either use ready mix cement or mix it yourself.
Mixing it yourself means combining Portland cement, sand, crushed rock (or gravel), and water. The amounts are 1 part Portland cement to 2 parts sand and 3 parts gravel.
One of the easiest methods is to use a square shovel as a measuring tool (for example: 1 shovel cement, 2 shovels sand, 3 shovels gravel).
Place the three dry ingredients in the cement mixer. With the mixer running, begin to add water. Keep adding water until you have a consistency that's well mixed but not too loose. Just enough to pour easily when the mixture is emptied into a wheel barrow.
Pouring Cement
Whether you mix the cement yourself or have it delivered by barrel truck, you'll need to level the cement once it's poured into the forms.
For the most part, you need to pour enough cement that it can be pulled and leveled down to where it's level with the top of the form boards. In other words, you'll initially have slightly more cement than it takes to fill up the formed area.
Using the screed board, pull the excess cement starting from one end of the forms to the other. The easiest method to do this is to use a back and forth sawing motion as you pull toward you. Also, if the area you're pouring is rather wide, you'll need to have someone else help you by working the opposite end of the screed board.
Once the cement is leveled, you'll need to tamp the entire area. With a strong grip on the handles, repeatedly raise and lower the tamper quickly and forcefully against the surface of the cement.
Tamping allows the larger aggregate (gravel or crushed rock) to "settle" toward the bottom, leaving a more workable creamy mixture at the top. (This is an extremely messy process so be prepared to get splattered with cement.)
The next step is to smooth the surface using a bullfloat. This is done by pushing the bullfloat away from you with the handle lowered and then pulling it back with the handle raised high. (Raising and lowering the handle controls the angle of the bullfloat.)
Keep repeating the process until the entire surface is smoothed out. (If you need to reposition the bullfloat, bring it toward you and then carefully lift it straight up off the cement and back down again.)
Once that's done, and after the cement has set up enough, you can begin to "finish" the surface of the cement using hand trowels. For best results, sweep a steel trowel back and forth, pressing slightly harder on the left edge when moving the trowel to the right, pressing slightly harder on the right edge when moving the trowel to the left.
You should also run an edger along the perimeter. Aside from providing a nice finished look, it helps prevent the edge of dried concrete from chipping.
Allow the concrete to cure for a couple of days before removing the forms.
Things To Consider
If you're pouring a large slab, you'll need to reinforce it with wire. You can use wire remesh that's made specifically for pouring concrete or regular fencing with a similar grid pattern. Position bricks or rocks for the wire to rest on so it's raised about 1-1/2" above the ground throughout the entire form area.
Control joints should also be added to larger slabs to prevent random cracking. Place a board across the width of the slab and use it as a guide to "cut" grooves every 6 to 8 feet with a grooving tool.
For a textured non-skid surface, simply drag the bristles of a broom over the entire slab. For best results, make sure you wait until the concrete has almost completely set up. Otherwise, you won't get the right texture. (It also helps if you clean the bristles after a couple of passes.)
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