|Office: (734) 260-3410 Fax: (734) 895-7251
You want to put in a patio, driveway or sidewalk, and you have decided to use concrete. One
thing to know before you put in your concrete all concrete cracks. Concrete typically consists
of cement, rock, sand and water. In the fresh or plastic stage, concrete is fluid. As it hardens,
the cement and water begin to shrink, and the stresses created by this shrinking cannot be
overcome by the small amount of strength developed by the young concrete. If you place the
concrete on a windy day, the top may start to harden before the bottom, which will cause the
concrete to shrink unevenly (plastic shrinkage cracks.) Also, if the ground underneath the
concrete is not level, there will be an unequal dragging force while the concrete shrinks, also
causing stresses the new concrete cannot withstand.
Before we place your concrete, we make sure your subgrade (ground beneath the concrete) is
thoroughly compacted and level. This will help ensure there are no soft spots. We then apply a
layer of sand, this will help achieve a totally level surface and allow a consistent friction to the
shrinking concrete. We may use a wire mesh for reinforcement, we also may use
reinforcement bars (rebar) tied together with steel wire, but spacing and size requirements vary
based on load and soil conditions. Another alternative to have the ready mix concrete company
supply fibers to the mix. These fibers are usually nylon or polypropylene. They help keep the
cracking of the concrete on a micro level instead of a macro level (where you can see the
cracks with your naked eye.) Steel reinforcement also helps keep cracking in check, but if
cracking does occur, the steel, when properly placed in the concrete, will hold the concrete
together, whereas fibers will not do that.
Contraction joints are the secret to prevent cracking. By placing contraction joints that are at
least 1/4th the depth of the concrete and on intervals of 25 to 30 times the depth of the
concrete, this will almost ensure there will be no visible cracking in your concrete. This jointing
method helps the concrete crack at the weakest point. This is why it is so important for the
joints to be deep enough. Variations in subgrade levels could cause greater stress in the
concrete in an area where the joint is not’t deep enough, and the concrete will crack outside the
joint. It takes about two weeks for your concrete to cure. Then we come and seal the joints.
This will prevent water from migrating into the subgrade and expanding and contracting, or
getting into the joints and freezing, causing the water to expand and breaking out the concrete
around the joints.
Repairing Cracks in Your Concrete
Concrete cracks, chips and broken or flaking areas in concrete are not only unsightly; they can
lead to further deterioration of the surface. The result is a costly concrete driveway, concrete
sidewalk or replacement project as opposed to a simple repair. Inspect your concrete and
masonry walls, walks and concrete slabs for damage on a regular basis.
Call REO Construction Co. for a free quote to repair or replace your concrete!