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Here is the story, I hired a concrete sub to pour a 16′ x 18′ patio.
The sub told me he would have two people to pour and finish, well guess what? only one. The problem is the finish, I believe he began to lose the finish so he put more water on it to get more paste. 1/4 of the concrete is discolored and looks very unprofessional. The concrete sub said that the color will blend in over time. I asked how long? when? are you sure?
What if it doesn’t? What can be done to correct the problem?
So fellow tradesmen please give me some advice and knowledge of the discoloration will the color blend. I have one more question how long does concrete take to cure? to Dry?
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It is normally considered fully cured in 28 days, but some will answer that it takes months or years for the cement to fully hydrate and cure.
Depending on the mix and weather, it's usually dry enouigh to walk on the next day.
*James,It sounds like when your contractor got behind, the mix got "hot" and he added water to slow the surface hardening. Unfortunately adding excess water weakens concrete. A "dull" color on the concrete surface may indicate weakness. I have seen this numerous times and in all cases the concrete surface powdered away (after the first year) and left the rough aggregate layer underneath.I would put your contractor on written notice that the finish is unacceptable and ask for a remedy. You could contact a concrete testing agency who for a price would send out a technician. This tech could use a rebound hammer to check on the strength of the concrete. If the concrete strength is less than code requirements you could ask for replacement of the slab.
*Thanks for the input. all the info I get will greatly help James
*Here reality. If you already paid the guy, you out of luck. If you do not have a sign spec contract, your out of luck. If you donot have a quality contract, your out of luck. Now the color will fade over time. all concrete is different colors from truck to truck, this is common. the rebound hammer is a joke. A core will be need to be taken. Bldg code claims only 2500 psi. So if it has no cracks and you have paid the guy you gotta live with it. Now if you havenot paid the guy, cut $500 from his price.Oh yea, I,m a concrete tech, we charge $30 hour two hour minimum with $150 for engineer report. Is it really worth it.
*Jonnie,When the rebound hammer goes "thud" and leaves a depression this indicates a lack of compressive strength. I agree that a rebound hammer has deficiency for telling 3000psi from 3200psi and depends on variables. Rebound hammer takes two minutes. Core drilling is second step. My suggestion was to get an independent person to make an assesment and a rebound hammer used as a first assesment. Since you are a concrete tech then you know what overwet concrete looks like and how it has an identifiable "look" and you could give an honest educated opinion. An independent professional opinion holds weight when it comes to assesing quality.James, don't hire anybody...go hit it with a regular hammer (if the concrete is at least two weeks old) and if it leaves a hammer dent then it is deficiant. $500 credit might not cover the shorter life of this slab.Concrete increases in strength rapidly at first and then slower over time. At seven days you might have 3/4 of its design strength. Twenty-eight days is when concrete is supposed to reach its design strength. Concrete with proper curing continues to gain stregth over time. If concrete is allowed to "dry" then the chemical reaction of the cement hydration is stopped and the concrete will not gain more strength.
*I, myself do not like the rebound test, itself. yes we use them daily. I just feel in takes alot just to be able to read the rebound results and then they are about 40 % accuracy. Its a fish shoot. You can rebound a aggregate and think you have good concrete then hit a soft spot. My main point was. Is it worth it for a patio and did you pay the guy. If it was my property, I would pay the concrete supplier and tell the labor to take a walk, he just did a free job. If its only color thats bad put some split brick on top
*I am looking for a remodeling oriented newsletter that I can purchase to mail to my customers as a way of keeping my name in front of them. Does anybody know of a good one.Mark R
*Jonnie, you are correct.Mark, you probably will not get an answer burried in this thread. Repost in the main page where it says "Add Discussion".
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Here is the story, I hired a concrete sub to pour a 16' x 18' patio.
The sub told me he would have two people to pour and finish, well guess what? only one. The problem is the finish, I believe he began to lose the finish so he put more water on it to get more paste. 1/4 of the concrete is discolored and looks very unprofessional. The concrete sub said that the color will blend in over time. I asked how long? when? are you sure?
What if it doesn't? What can be done to correct the problem?
So fellow tradesmen please give me some advice and knowledge of the discoloration will the color blend. I have one more question how long does concrete take to cure? to Dry?