Hi y'all. Long weekend in Phx is completed. Granbrats are cute as can be. Brats are doing well, had their marriage blessed in the church Saturday evening :D. Glad I made the trip for it.
Concrete and air. In the applications I used air, it increases workability at a lower cement/water ratio. Lower ratio = Higher strength to some extent. The air also adds a minute amount of flexibility to the concrete. The voids should indeed increase any insulating properties. 3-4% air was the consistency we used mostly. I'm not sure if that 3-4% would directly change the placed volume by exact %age. Think of most any poured in place concrete bridge as "concrete re-enforced" steel, not the opposite. For a spooky feeling stand on a concrete bridge while a few motor vehicles roll over it :D You'll feel it wiggle around under your feet :rolleyes:. As far as cure time goes, keeping it hydrated for 28 days gives maximum strength. No telling what chemicals they have enlisted in the search for the perfect concrete since I stopped messin' with it 20 years ago. I do believe that probably half of the concrete failures that occur are the result of those admixtures. That airport bridge collapse in Florida a couple of years ago is a good example. Too many chemicals and to make matters worse they stripped the false work before it was out of cure. They did so because they used accelerators and had it in their tiny minds it was done curing.