Jim
Air (air-entrained)in concrete does several things. It
decreases freeze thaw cycle damage, decreases
permeability (less porous), increases workability
(makes it seem slicker when finnishing it). Has been
used for years.
Rebars' main purpose is to add strength, wire mesh is
better at reducing cracking.
Newer products worth considering are the fibre
previously mentioned and possibly some plasticizer
(lets you use less water). The less water you use the
stronger the concrete.
You also want to control the drying process (slow is
good) this can be done with a spray on curing compound
(use an old pump up tree sprayer), covering with
plastic, or just keeping the surface moist.
I would use a 5 sack mix (5 sacks of cement to make
one cu yard concrete.
Talk to your material company if using redimix those
guys are usually a great source of information.
Depending on the size of your slab and planned shop
layout you can influence possible crack location by
running a jointer (tool that puts grooves in sidewalks
ect). With concrete somtimes it cracks somtimes it
don't, if you are lucky it will follow the joint.
Good luck
Steve
--- New Mexico Jim <ADvent@thuntek.net> wrote:
> What does the air do? thx
>
> Floyd Humphries wrote:
>
> > Concrete Garage Floor
> > You might want to spray a curing membrane on the
> finished floor
> > this will help eliminate the shrinkage cracks,
> also keep the concrete as
> > dry as
> > possible and still be workable.it makes a little
> more work but the strength of
> > the finished concrete will be higher. also ask the
> redi mix company if they
> > can
> > put a little air in it (this is not a joke)
> > Floyd
> > 49 3100 5 window deluxe
> >
> > oletrucks is devoted to Chevy and GM trucks built
> between 1941 and 1959
>
> oletrucks is devoted to Chevy and GM trucks built
> between 1941 and 1959
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