The Down Range Forum
Member Section => Down Range Cafe => Topic started by: billt on March 11, 2018, 09:03:23 AM
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TAB, you know concrete and construction, so I want your opinion on this. Yesterday I had my driveway widened. The whole pour was around 8 yards total. The guy said the stuff he poured was 3,500 PSI concrete. (The receipt from the concrete outfit confirmed this). They started pouring around 7:00 AM. The concrete truck pulled away and left from my house around 8:30 AM yesterday morning. It was cloudy and around 74 degrees. The humidity was 25%.
The crew did a real nice job finishing it. And they pulled the forms, cleaned and packed up, and left around 11:00 AM. Around 4:30 PM we got a light sprinkle of rain. Just enough to barely wet the concrete. Overnight we got a few more sprinkles. All total not even a 1/10th of an inch of rain total. This morning the new poured concrete was wet to the touch, and seemed hard. I don't know $h!t about concrete. Do I have anything to worry about?
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Concrete doesn’t dry, it cures!
Keeping it wet helps harden the cure.
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Concrete doesn’t dry, it cures!
Keeping it wet helps harden the cure.
That's what I've read. I know when I had my pool put in, they told me to keep misting it down with the hose, and not let it get too dry. I asked about it puddling up at the bottom, and they said it won't hurt it at all. That was 20 years ago and my pool is still like new. But I don't know if it's the same type of concrete that they used in my driveway? I think it had to be much stiffer.
It just scares me to see water on it so soon after it was poured. But as I said, I don't know $h!t about concrete.
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I’m guessing there’s probably a dozen different concrete types.
Water evaporates from the mix after the pour, keeping it covered and damp helps. I’m surprised the company didn’t give you some advice on how to allow the pour to cure properly. I did a large patch in the driveway some years back and it was 8 to 10 inches thick in the area that I corrected. It took about 7 to 8 days to cure properly.
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They told me it would reach 75% "strength" in about 3 days. And not to park any vehicles on it for about a week. From what I've read, it takes around 30 days or more to cure to 100% "strength". I don't know.
Right before they left they sprayed a white, milky looking, water soluble "curing agent / sealer" on it. That all dried before it started to sprinkle. I just went out and looked it over real good, and it seems to be setting up nicely.
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If concrete is kept moist, it will continue to cure for up to a year. That doesn't mean it isn't ready for use long before the year is up. Just that it will continue to get harder over time.
Drying it more rapidly actually inhibits the curing process. After the first couple of days, even large quantities of rain should have little to no impact on your pour and will actually prove beneficial to the long term strength.
Crusader Rabbit
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Thanks. You guys are telling me what I want to hear. The clouds are breaking up, and the Sun is out. It's supposed to be sunny and in the low 80's until Thursday. Then we're supposed to get a little more rain.
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It getting wet was a good thing, it slows down the curing process. It never stops curing. With out getting super technical, it reacts with co2 in the air in a exothermal (produces heat) chemical reaction.
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Thanks TAB.
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Most people say that it reaches it's full strength in 28 days, but should be at 75% strength in 7 days. TAB is right about the curing never stopping. The concrete in the Hoover Dam is still curing. The process starts out fast but constantly slows down.
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I most likely won't park on it for a good month. Why push it? I've lived without it for 20 years. So another month isn't going to kill me.
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I tell people 2 weeks min. Month is better
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In the funeral business, the burial vaults are strength rated based on mix and standard seven day cure. However, they are tested at much stronger, because even though they are installed at seven days, the day after the pour they are coated and sealed with an asphalt product, and prior to installation they are painted. This coating and sealing, combined with full earth burial between seven and 14 days slows the cure and increases the actual strength.
Up here in snow country our biggest concern with fresh concrete is chloride. Road deicers (salt and calcium chloride) harm the product. It is best to protect fresh concrete from these items for a 12 month minimum. When we built the funeral home we poured the drive apron and entry way in September. Even though the concrete was sealed at pour and again with another agent 30 days later, the drive apron was heavily spalled within a couple weeks of the first heavy snow from the salt mix the city threw on the roads. Even though we tried to avoid all deicers on the entry platform and back garage platform, the tracked and dripped deicers created slight spalling. I avoided it in the garage. I attribute that to that floor being poured in early summer, and that the garage was heated and I washed the vehicles in there.
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The reason why calcium chloride is a problem, it interrupts the silicon dioxide calcium carbonate reaction that actually produces concrete. Basically what happens is it binds to the calcium from the chloride instead of the carbonate
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I tell people 2 weeks min. Month is better
That's what we always promulgated when we poured driveways when I was a kid.
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Can anyone recommend a good concrete sealer that will protect from automotive oil drippings soaking into and staining the concrete? If I'm going to do it, I would just as soon do it after it cures, and before I start using it. That way I can eliminate the cleaning, pressure washing, etc.
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Is there a moisture barrier underneath It? If not, no sealer will hold up.
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Is there a moisture barrier underneath It?
If you mean like plastic sheeting or woven material, no. Just a layer of gravel. That's all they use out here.
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No sealer is going too stick then. Depending on the air entrapment it may let water right thru. You said it was 3500 psi, which is a standard rating in strength, but does not say much about the mix itself. One would assume it's 1/2 stone, and 6% air entrapment which is the industry standard for a drive way.
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If you mean like plastic sheeting or woven material, no. Just a layer of gravel. That's all they use out here.
When I had my driveway extended we put down a lot of sand and no gravel. I wonder which is better?
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You want both.
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In living both in Illinois and Arizona, I've never seen anything put down under concrete.
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You want both.
Gravel for a more solid base and sand to fill in the gaps?
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Gravel for base and sand for better finishing
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All layers compacted thoroughly.
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Can anyone recommend a good concrete sealer that will protect from automotive oil drippings soaking into and staining the concrete? If I'm going to do it, I would just as soon do it after it cures, and before I start using it. That way I can eliminate the cleaning, pressure washing, etc.
I know it is more than a sealer, but when we visit Arizona I see a lot of driveways with the epoxy coating that we use inside. I don't know how it stands up to UV, but it stands up well against oils, fuels, chemicals, and even tire wear.
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I know it is more than a sealer, but when we visit Arizona I see a lot of driveways with the epoxy coating that we use inside. I don't know how it stands up to UV, but it stands up well against oils, fuels, chemicals, and even tire wear.
If that's what I think it is it's supposed to stand up to urine on barn floors. I didn't know anyone used it on concrete outdoors. I learn a lot interesting little tidbits on here.
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If that's what I think it is it's supposed to stand up to urine on barn floors. I didn't know anyone used it on concrete outdoors. I learn a lot interesting little tidbits on here.
they make if stabilised products, but once again with out a moisture barrier it will not hold up. Not too mention the concrete used for that environment is much better then used on a drive way.
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The problem with the Epoxy Coatings is the cost. My neighbor just had the inside of his garage done, and it looks beautiful. But all total it cost him over $3.80 @ sq. ft. installed. You can find a closeout on ceramic tile for almost as much.
A lot of homes in Sun City do the Epoxy Coating on the entire driveway. It looks great, and wears well. Again, the problem is cost. They make clear, high gloss sealers that look almost as good, but are far cheaper and easier to apply.
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they make if stabilised products, but once again with out a moisture barrier it will not hold up. Not too mention the concrete used for that environment is much better then used on a drive way.
I don't know what barns you have built, but it is no different in our region. Shop floors, barn floors, garage floors, and driveways ... All the same mix.
They are using it on garage floors nationwide, and most have no vapor barriers. Our local Ambulance garage has it, and it was applied in the mid 80's..
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Every barn/ garage/ house I have ever built has had one. The mix is also very different from a drive way mix, in strength and composition.
I have seen so many moisture ruined epoxy floors it is not even funny. I was in industrial coatings for years as a boomer.
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Well, this morning it's been 5 days, and it's curing nicely. It's getting much lighter and whiter with each passing day. At night it's been getting down around the low 50's. And during the day it's been in the upper 70's and almost 80.
I swept it but I still haven't hosed it off. I'll give it until the end of next week. I'm in no hurry.
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Sprinkling water on it is actually good. Just sprinkle.
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Did you hear about the guy who shoveled cement with a pitchfork?
He was a mortar forker. ::)