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Question DetailsAsked on 3/27/2013

We had a concrete driveway installed in September of 2011. We now have pop outs every foot or so. Is this the contractor's problem?

The driveway was installed in September of 2011. It looked great until this winter. The pop outs are occurring everywhere- including the newly installed walkway. We never salt our driveway, so chemicals aren't the problem. Is it too late to contact the original contractor? This was an expensive undertaking. I thought concrete was supposed to last longer than 18 months.

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3 Answers

Voted Best Answer
1
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It is difficult to tell what the problem may be. It sound like the cement was improperly mixed. You could contact the company that did the work but they probably won't warrant their work over a year.

What often happens is during the winter you may experience a freeze/thaw cycle. During the thaw, water enters the tiny cracks and gets into the cement. Then at night when the temperatures get below freezing the water expands and chips away at the cement. It is recommended that the cement be sealed with a sealer to help prevent further damge from occurring.

Source: http://homefrontinspection.com

Answered 6 years ago by Homefront Inspection

1
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First contact the original contractor to have them offer an opinion. Though it may be out of warranty (check your contract) they may have a reason for the problem such as heaving or other natural causes. They might also admit a problem with the pour if they are honest. They may even offer some sort of fix, but possibly share the cost with you if out of warranty. If they seem unknowledgeable or uncaring find someone else to give you an opinion who can see the site and identify the cause.

Todd Shell
Todd's Home Services
San Antonio, TX

Answered 6 years ago by Todd's Home Services

1
Vote

Several possible causes here:

If concentrated under where you park the cars and where you walk on the sidewalk and they use salt on the streets in your area, then that is possibly the cause, dripping from the cars when they are parked, plus tracking by foot onto your walk. If this is the cause, you probably have white salt encrustation along the walks and on your porch and doormats and entry inthe winter and spring. Even if this is the cause, should not be happening to any extent in two winters.

Another possibility is the wire mesh was installed too high (or the slab was shallower than designed, making the cover too thin) - if rusty wire is exposed in the bottom of the popout if you brush or wash them out, then this may be the problem. (The mesh should have minimum 2 inch concrete cover so it does not severly rust, which causes popouts as rust expands many fold when it forms). If this is the problem, it tends to form a rectangular or linear pattern of cracks reflacting the position of the mesh wires, followed by popouts.

If general over the entire surface and no square or rectangular pattern, then he probably failed to put air entraining agent (or too much) into the mix. This is a chemical mixed in that forms lots of very small air voids in the concrete, which then provide space for expanding freezing moisture to move into, so the expanding ice does not break the concrete. Too little leaves the freezing water nowhere to expand so it causes cracks and popouts and eventual general surface degradtion to gravel. Way too much causes the tiny air pockets to combine into open air channels and air pockets that destroy the benefit of the distributed tiny pockets, collect water and promote frost damage.

If they placed the concrete when nighttime temps went below 45 degrees in the first week this dramatically reduces strength, and popouts and cracks can result from this.

Could have been a poor mix - inadequate cement, wrong type of cement for local aggregate and water, etc - though unlikely if came from a commercial readymix plant in a transit truck, rather than on-site mixed in a portable mixer. However, if they then added water to the truck to make the concrete flow easier (a common stunt in hot weather, when the truck arrives with the concrete already starting to set due to high heat), this weakens the mix permanently.

Could also be because they placed the slabs and then did not water cure it. Concrete gains strength from chemical combination of water with the cement, NOT from drying as most people think, so it needs all the water in the mix to cure properly. Therefore, it needs to be kept moist for 28 days to reach its design strength. If it dries out before it reaches initial "green-cure" strength, then it stops curing almost totally and has minimal strength. After final steel trowelling, they should have sprayed on a curing compound (a curing sealant to keep the wter in) on it, AND kept it and the edge forms surface-wet and covered it with plastic sheeting for at least 3-7 days. A permanent waterproofing sealer should then have been applied about four weeks after initial placement to protect against staining and salt penetration. If this was not done, it should be totally replaced.

At any rate, whatever the cause, this should not be happening in the first couple years on a new driveway - usually takes 5-10 years to first appear, and 15 or more years to get general in coverage.

Repair is not cheap, assuming inadequate concrete strength or mix, curing, or freezing was not the problem. Repair involves powered "bush hammering" or power carbide cutter scouring of the entire surface with a jagged-face tool (looks like the spiky face on a meat tenderizer hammer, or a heavy wheeled rotary tool with carbide rollers) to break loose and remove any cracked surficial concrete (which may or may not show at the surface), then sand or shot blasting to remove concrete "laittance" from the aggregate and derust any exposed mesh, then repairing the surface.

If the problem was too shallow a mesh placement, then a 1 inch or thicker small-aggregate epocy-modified concrete overlay is called for (or total replacement of the slabs). If due to deicing salt, then a full-surface epoxy modified concrete resurfacing grout would be used - spread and floated over the entire surface. In either case, the new surface should be cured as noted above, then after curing is done, have a permanent sealer sprayed on it. This type of fix will NOT be as good as new, but if done right can last 10 years or so before starting to delaminate.

Your contractor should fix this as a defect, but convincing him to do so may take some doing. If at all possible, convince him that total removal and proper replacement is the quickest solution, though it means more out-of-pocket cost for him. If he does not respond, his contractor's association (if he belongs to one) or the BBB may help put pressure on. If they do not succeed, then bad reviews on sites like Angie's, complaint to your city or state consumer protection bureau and the contractor licensing board, and finally lawsuit are your final options.

If he was supposed to be licensed, bonded and insured and was not, that could strengthen your attempt to get the government agencies on his case, although in that case he would not legally be able to fix it - would have to pay for another contractor to pay for it.

If he does not come through, you could try filinga claim with his bonding company for inadequste job performance, but given the time passed and presuming you gave him final payment upon completion, that is a long shot.

Your local building department may help, particularly if they have codes requiring specific construction, curing, etc.

You may have to get a local civil engineering consulting firm with materials lab to come out and do an assessment, and take a core or two to test the concrete for strength and evidence of proper air entrainment. This should cost $250-500 including testing, and would provide evidence for a legal claim against the contractor. Of course, if he gave a specific warranty and you are past that point in time, your legal recourse becomes really a gamble. Only an attorney with experience in construction contract claims could advise you on odds of success in that, and unlikely worth the cost because palintiffs usually bear their own legal cost unless you can prove fraud. However, a small claims court action might be to your advantage, especially if your local court allows claims to say $5,000 or $10,000 instead of the $500 in some areas.

Good luck

Answered 6 years ago by LCD

0
Votes

The problem is that the contractor used agregate that absorbs water. In winter the water freezes and in doing so expands. The result is the concrete pops off and the pressure relieved. You can confirm that this is the correct answer by looking at each pop. You will see a piece of agregate at the bottom. I hate to tell you but you will fix these pops after every winter.

Answered 4 years ago by madaduff




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