Fixit: Concrete should last for many years

Q What causes concrete to disintegrate in less than two years? Can anything be done about it?

A Concrete should last much longer that. There are sections of concrete sidewalks around city lakes stamped WPA (Work Projects Administration) from the 1930s, and they are still in great shape.

Concrete is a mix of cement, aggregate (gravel-like mix), water and other materials. Concrete is hard and durable, but it can fail prematurely in a number of ways:

• Scaling is when the top layer flakes off.

• Mortar flaking is similar in appearance but occurs over individual aggregate (small stones) particles.

• Popouts occur when certain types of rock freeze, expand and pop out of the concrete, leaving small holes in the surface.

The reasons for these failings usually are:

• Problems with installation, such as poor mix design and finishing. Inadequate curing can prevent concrete from gaining the proper strength before freezing weather sets in.

A severe winter with saturated concrete that freezes, long periods of extreme cold, or repeated freeze and thaw cycles can cause these problems to show up rapidly.

That said, concrete should not be disintegrating two years after installation.

Have your concrete contractor come out and view the damage. You probably will have to replace the concrete.

If you don't get satisfaction from your contractor, contact the Consumer Division of the Attorney General's Office at 651-296-3353 or 1-800-657-3787. Or go to www.ag.state.mn.us and click on Consumer Complaints.