Question

My concrete driveway is cracking. Should I replace it or fix it?

Asked by Sherry
Flint, TX

I have a 200-ft. driveway. It starts at a 40-degree angle and levels off at about a 20-degree angle in front of the garage. It is concrete now, but is cracked and washing out under part of one side. We have to replace or fix it; wondering if you have any suggestions. We live in a forested area, and the driveway is not landscaped or maintained along one side.

Answer

David Edwards PhD

Answered by David Edwards PhD

Santa Clara, CA

EarthBound Homes

September 20, 2010

Concrete is the most durable material that you can use for a driveway. It does have a high entrained energy value, but also lasts much longer than asphalt or crushed stone.

  • The problem you seem to be having is that water is penetrating the support under the concrete and undermining its integrity, resulting in cracks and washing out.
  • If you can solve this problem, the concrete that is cracked can be replaced and the surface you have that is still good should last you for decades longer.

The key to all concrete problems is the base, or what the concrete is sitting on. Concrete is great for wear-and-tear and great for compression, but is not very good for spanning distances unless it is designed to do so, and typical slab-on-grade 4" driveway slabs are not designed to do so.

  • I recommend you remove what is significantly broken and come up with a good water mitigation plan, preferably with the consultation of a good civil engineer, that keeps the water away from the concrete driveway.
  • This can be as easy as a concrete culvert running along the uphill side of the driveway, with the appropriately placed pipes running downhill and under the driveway and away from the supporting substrate, usually crushed rock or aggregate.
  • You have an expensive material for a 200-foot-long driveway, so your first effort should be to retain this material, saving you money and saving the environment the energy needed to replace the concrete you already have.
  • Besides, without fixing the underlying problem, i.e., drainage, the same thing will happen to any driveway material you install.

One more thing: the civil engineer may seem to cost too much at first, but

  • just think how much it would cost to replace your 200-foot driveway every 10 years. 
  • Search Green Home Guide's directory for green engineers near you.

Good luck, and I hope this helps.


For more information:

Read Rick Goyette's Q&A "What are the green options for driveways?"

Tagged In: green cost, durability

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