Concerns about concrete driveway

[duncanblizzard]

Hopefully this is posted in the right place and appropriate for this forum.

We had a driveway poured and have concerns about how it was done. I have included some pictures. These pictures were taken just over two weeks after the pour.

The first shows it dry. There are still some dark sections, but they are gradually disappearing. The next few pictures show it wet. These almost appear to be cracks throughout -- like a bunch of puzzle pieces. We don't believe it should be like this. The last two pictures show the white (minerals?) we end up hosing off regularly. Potentially these will lessen over time, but I don't know if they signal a problem.

From the research we've done, some mistakes appear to have been made.

1. It was poured on the front end of a heat wave. It was in the low '90's when poured and increased closer to 100 degrees in the couple of days after it was poured.

2. No sheeting was used and it was not kept wet. It was poured early in the morning (truck arrived at 7 am). The lead came back that evening to hose it down and told us to hose it down daily after that. No plastic sheeting was used to retain moisture. We're in California so not nearly as humid as many states but not totally dry either.

Are our concerns about this driveway justified?

Thanks!

 

[Chaznsc]

You've got some crazing going on there. Top dried out too fast. Ugly but not structural. The issue will be if those pieces start to spall off.

Did they not broom finish it? Looks a little smooth to me.

 

[duncanblizzard]

Yes, I saw them broom it, so I know it was done. It may not have been adequate, though.

In looking up info on crazing, it doesn't look like anything can be done after the fact. I feared this was a structural issue, and hopefully it won't become one.

I noticed that the driveway doesn't dry as quickly as I think it should. I'm guessing that the crazing holds the moisture longer.

Is there any concern about the white crystalizing that we're seeing? It's most apparent at the level portions of the pour where the water doesn't drain as rapidly (or in one spot actually pools).

Thanks!

 

[ScaldedDog]

Mr Blizzard, I'm glad you posted this. My garage floor looks like your top photos, and I never new what it was before now.

Mark

 

[Rookie2]

did you hose it down as they ask ?

 

[duncanblizzard]

Oh yes, we hosed it down daily as instructed. Given the heat, though, it apparently dried far faster than it should have. During the few days right after it was poured when it was close to 100 degrees, it was hard to keep the driveway wet because it was so hot and the water immediately evaporated.

 

[bobscogin]

What was the slump? Looks to me like there was excess bleed water on the surface during the finishing process

Bob

 

[duncanblizzard]

I had to look up slump and don't know what it was for this project. It looks like slump is a measure of wetness and/or consistency. I watched the pour as well as all of the working of the concrete, but I don't have the knowledge to know if it was done right or not. I hired someone licensed and insured who came highly recommended and expected him to bring the expertise.

On the issue of consistency, the driveway and side yard were done using a single load of 10 cubic meters. Half of the parkway patch was also done with that load, but an additional amount was brought in to finish the parkway. The parkway section appears to have the least issues. It's by far the smallest section and was done last, but I don't know what effects that would have. That section gets no shade at any portion of the day. Portions of the driveway and side yard get increasing shade in the afternoon/evening.

The worst section appears to be the side yard although the driveway is also full of crazing. They moved from the driveway toward the sideyard (which is all one single slab), so the sideyard was worked last -- well, the parkway was done after the sideyard.

 

[duncanblizzard]

I've attached a picture I took of it prepped for the pour. You can see the basic layout. The foreground is the driveway, and it goes right into the sideyard. You can see the small parkway section out by the car.

 

[Rodhotz]

My driveway looked just like that and it has been 20+ years and no problem with it poping or any other separating problems.The white is calcium in the mix it will go away after some time. If you do need to pull it up it will be hell with all that steel in it. Just keep watering it for a while more and the white will come off.

 

[Tunajoe]

I was told by my concrete contractor he would guarantee 2 things;
1. The concrete will get hard.
2. the concrete will crack.

 

[Steevo]

Wow, that is some impressive steel in that driveway.

 

[duncanblizzard]

I was told by my concrete contractor he would guarantee 2 things;
1. The concrete will get hard.
2. the concrete will crack.

We know that concrete cracks, but this crazing is not normal. The entire driveway is a mass of small cracks that showed up right after it was poured. And I've never seen crazing on other concrete driveways or parkways. It shouldn't have happened and from what I'm reading is due to incorrect curing.

 

[ConCretin]

Crazing is basically shrinkage cracks in the cement paste on the surface of the slab. They aren't structural and usually don't result in durability issues - they just look unsightly.

Crazing is caused by a number of factors including inadequate curing, too much water in the mix, finishing while bleed water is still present or adding water to the surface during finishing.

My guess is that a couple of these were to blame here and curing is probably one of them. Spraying a slab once a day isn't enough. Proper curing requires keeping the slab in a continuously moist condition for at least seven days.

The simplest method is to wet the slab down well and then cover it with poly.

Sorry you have problems with your driveway but at least they aren't fatal.

 

[FORMUD]

The only way wet curing works is if you keep it wet for 7 to 10 days and not let it dry. Burlap or plastic will help hold the water in, but you will run the risk of staining the concrete. I've heard of people flooding the slab by building a dam around the outside edge and filling the inside with water.
Wet curing would not have helped with crazing like you have. The top of the slab dried to quickly while it was being finshed....Heat or wind could make this happen. As stated above, it doesn't hurt the concrete but it can make it look ugly.

 

[duncanblizzard]

Thank you for all of your replies. I'm getting a much better feel for the causes of this crazing. It is unsightly for the entire driveway to be a mass of cracks much like shattered glass. And of course everyone sees our driveway. It's right there at the sidewalk.

It sounds like even doing the pour in a heat wave was an issue. The morning sun beats down upon that entire slab. He said he started it at 7 am to save his workers the heat, but in doing so, he also most likely caused much of the crazing. It was definitely drying as they were working the slab. As you can see, it's a fairly large piece of concrete, and there's even a little more that wraps up around the house that isn't visible in the picture.

I'm going to call him and have a talk about the issue. He told me early on that this would all go away, but it obviously won't. It's been more than a month since the pour, and the cracking is there to stay.

Thanks again! (although I'd still appreciate more responses if I have more to learn about the issue)

 

[JakeKohl]

I'm sure there is a designer somewhere that would call that a feature.

 

[Zeke]

It will take some time, but it will look a lot better down the road.

 

[dadsEH]

Just paint it!!

 

[duncanblizzard]

Our talk didn't go well. The contractor swears all concrete has crazing and that it has nothing to do with cracking. I showed him the sidewalk doesn't have crazing. He swears after a year of curing this will be gone, but I know that's not the case.

We left with him promising to look up crazing and understand what causes it, how to prevent it, and that it is a defect. Then we'll talk again.

 

[Benw455]

How does it sound when you tap on it?

 

[duncanblizzard]

We have some follow on questions. The driveway and sideyard were poured two months ago. The dark sections are progressively fading, but tooling marks are still very visible. We're also seeing more color variation. There is not only the white coloring that we've been seeing but there's now some yellow coloring.

We've been out of town for the last week, and it's clear the guy who poured it has been by and done things. He told us an acid wash would fix the crazing and tooling marks, but we've found no evidence of that in any literature. Is there any truth to his claim that the acid wash will improve crazing or tooling marks in the concrete? We're wondering if he was experimenting while we were gone. Would acid wash cause the yellowish coloring?

Should we be concerned that the dark spots are still not fully gone two months after the pour? We no longer trust anything the person who did this says.

I've attached some pictures taken in the shade. If those aren't clear enough, we can get some in the sun in the morning.

 

[FarmerPete]

I feel your pain. I'm sure it's dissapointing to pay all that money and get left with a product that doesn't meet your expectations. It looks like this company didn't know what they were doing, or they weren't willing to put in the effort to do it right. Unfortunately, I don't know if there is much that can be done short of redoing all the work. If I was the contractor, I think I'd offer some kind of a rebate and call it good. If what other people said is true, the structure should be good. Is there any kind of a warranty they gave? Perhaps if you start to get pitting/damage you can pounce on them.

 

[bczygan]

Concrete flatwork is an art. Not all contractors art artisans of the highest caliber.

Getting a contract on paper that protects you from less than the best work is difficult.

The best protection is picking a contractor, based on his existing work.

But **** still happens.

You probably have no legal recourse and must depend on any remediation the contractor offers, if any.

 

[Jaguar Fan]

Talk to him about putting a concrete overlay (topping) on.

 

[duncanblizzard]

I was out there today with a neighbor inspecting it more thoroughly, and there are now noticeable cracks even when dry throughout large sections of the concrete. It's only been two months, and I have no idea how much further it's going to progress.

The pictures don't do it justice. I may have to put a colored liquid in there to really show the cracks, but I don't have confidence at all in the workmanship or integrity of the driveway. Even if it doesn't progress further, it will be a nightmare to keep clean. Everything will land in those cracks and be hard to get out. I guess a sealer or overlay might keep things from settling into the cracks, but these cracks can't be good.

 

[bczygan]

Too bad that the contractor didn't post a performance bond for the entire value of the job and have specifications with enough detail to force him to redo it.