help: bad concrete job

I'm putting in a shower prepan, and I'm following directions to make a thin, sandy layer. Mix: portland 1, sand 5. Next day, much of the concrete comes up with a wisk broom. What have I done wrong? Should I rip the rest of it up? I live in arizona, should I cover the concrete with tarp while it dries?
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You don't mention water. What directions are you following? Your underlayment could have sucked some moisture from your sand mix. I would rip it up and do it again. Dampen the area under the crete first or seal it.
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Cement 1 to 5 sounds like "drypack" to me. What you mixed is a far cry from concrete. Last time I did this I started laying on the mix while it was wet.
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I was attempting to make "Deck Mud".
Water: minimum amount for consistancy of sand-castle mix - not too dry, not too wet. I did not wet down the underlaying concrete pad before laying on my mix.
I'll rip up my bad lot, clean up, wet down the pad, and try again. Thanks!
also: Is there a minimum thickness for a such a mixture? Does anyone recommend a layer of thin set on the pad, to help the drypack stick?
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If the weather is hot, then cover the mix while it dries. Concrete sets by chemical reaction initiated by the water in the mix; if the water evaporates before the reaction is complete the concrete will not harden properly and will be dry and sandy (exactly as you described your mix to be!)
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I would go 3 sand to 1 cement
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