As I was in a home today working, just outside the window, concrete was being poured for a largish driveway. The pour itself was over quickly. But it took 2 guys the rest of the day to finish it. We all have watched this before. I came up with the idea of a roomba type machine for floating, smoothing, and "brushing" the flat work. Not to take away jobs, it would be remote controlled by a actual human being. But it would provide a more consistent finish and probably be much faster.

Maybe they already have this. But I thought my idea was amazing!

They could use a power float, but timing is everything WRT the finish. OTOH, the poorly-trained minkies who did my driveway should be shot. I guess I should have stayed home to watch.

I don't think you can do it faster unless you get faster concrete. That sounds like a joke, but I think it's the term they use for freeway concrete, for instance, that's driveable the next day after pouring. There you MUST have rapid finishing!

But I've only heard of this being used in a section of the 10 freeway that was being replaced a dozen years ago after a portion fell down in an earthquake. The contractor had a clause by which they'd be punished for being late and get bonuses for being early. They were several days early and I happened to drive over it the first day -- you could not feel the transition to the new concrete; it was dead flat; and the transition to the old freeway was perfect, too.

They use accelerant all the time, for various reasons. In the case of that freeway, it was demand for access but they also do it in cold weather, so the water doesn't freeze and the temperature doesn't inhibit curing in extreme cold. Since it's a chemical reaction that cures concrete, it generates heat and in high temperatures, they retard the curing. They used sugar in the past, but I don't know what they use now. Calcium chloride is a commonly used accelerant.

You're lucky the temperature extremes don't beat the crap out of the roads out there. Ours don't last long, so they often use concrete with asphalt on top- just to reduce the cost when the time comes for repair and replacement. Recently, the city voted to reduce or eliminate our ability to sue for vehicle damage when we hit large potholes.