Common concrete problems avoided with proper installation

INLAND EMPIRE – Concrete is a popular structural material among homeowners. One of the more affordable options for patios and other structures, concrete also can be durable and attractive. However, because no material is impervious to damage, concrete will need to be maintained, and certain problems can arise when concrete is not properly

installed.

Though an excellent material, concrete is not perfect. Even under ideal conditions, concrete can crack and breakage can occur. Here are some of the common complaints regarding concrete.

Scaling and spalling

Scaling and spalling is the crumbling effect of concrete. Very often this occurs from changes in climate, particularly freezing and thawing that causes structures to expand and contract. In areas where freezing and thawing conditions exist, masons should not overwork the concrete in an effort to keep an abundance of air in the mixture. Entrapped air will help buffer the freeze/thaw conditions.

Use of chemical fertilizers in and around concrete can also lead to scaling. Chemicals can break down the surface of the concrete. This is a particular problem when using rock salt and de-icing products during the winter. Over time, something as simple as table salt can etch concrete or cause spalling. The National Research Council’s Strategic Highway Research Program has found that magnesium chloride salt blends produce the least amount of damage on concrete surfaces.

Discoloration

Concrete should have a uniform color if the same mix is used. But discoloration can occur if water is added at the job site, the concrete is of varying thickness or if the material does not cure uniformly. Color issues can also occur if hard troweling is used on the exterior concrete.

Crazing

This is a phenomenon when the concrete shows several interconnected fine cracks. Cracks will appear when the concrete is damp. Usually this occurs when cement paste comes up to the surface and then shrinks. To avoid this, masons should be careful not to finish concrete until all water has evaporated and not sprinkle water onto the concrete while finishing it. Using a broom finish also can help.

Cracking

It can be disheartening to have a pristine concrete surface only to see cracks begin to form. Sometimes even with the best application, concrete can crack from subgrade settlement or shrinkage during drying and curing times. Utilizing flexible concrete joints to help with the expansion and contraction of the concrete can help. Also, including a low-shrinkage aggregate in the mix may alleviate major cracks.

Staining

Staining does not result from concrete installation or finishing. Staining occurs after the fact, when liquids or other materials discolor the concrete. This can happen when fluids from a car in a driveway stain the concrete. Leaves and plant matter left on the surface of the concrete may also cause staining.

The best way to alleviate stains is to prevent them in the first place. Always sweep or blow away debris. Maintain vehicles so they don’t leak fluid. Power washers can remove some stains, but it’s still best to prevent them in the first

place.

Problems can arise when building with concrete, but finding an installer who understands the nature of concrete can reduce the risk of those problems presenting themselves.

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