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Yesterday I poured a 9ft x 9ft x 5 inch slab and I am wondering if spraying the slab with water is better than using cure and seal during the curing process. I have also seen some people build a small dam around the slab to hold an inch or so of water. Which is the best way? Thanks.

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  • I have seen a lot of fresh house slabs and freshly poured sidewalks in Dallas TX and never saw any spraying with water. Is misting or sealing freshly poured concrete a new procedure to allow the use of a cheaper concrete to reach the target strength? Commented Apr 8, 2021 at 15:39
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    Many concrete crews in construction projects that don't have an engineer checking the concrete (i.e. basically all residential projects) are ignorant or careless of getting the most from the concrete by caring for it correctly once it's poured. It's hardly new - the ACI has published info about proper concrete curing for many decades.
    – Ecnerwal
    Commented Apr 8, 2021 at 17:29
  • And it's more important that a robust surface be attained in areas with actual seasons. Dallas doesn't qualify. :P
    – isherwood
    Commented Apr 9, 2021 at 13:02

2 Answers 2

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All of those methods do the same thing.

The sealant method is done one time, no additional sealant needed.

The water spray method needs to be done regularly, maybe every hour or so. The dam method has time involved for making the dam, but does not need to be maintained as much as water spray.

All these methods are done only after the last troweling is done and the surface will not be disturbed by anything placed on top of the concrete.

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Sealants are often used to reduce the maintenance requirement for fresh concrete (by municipal crews, for example). They're imperfect, though, so in hot, dry weather the curing concrete can still suffer moisture deficiency.

For that reason, regular misting is a marginally more reliable approach (assuming you're available to do so). It's also easier (no equipment or cleanup required) and cheaper.

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  • Great point about the heat issue with sealants.
    – Jack
    Commented Apr 8, 2021 at 14:18
  • Concrete needs water and carbon dioxide ( from air ) to cure , so spray is preferred. Commented Apr 8, 2021 at 14:25
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    Spray what? .
    – isherwood
    Commented Apr 8, 2021 at 14:30

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