That thick edge holds A LOT of heat and it will for quite awhile. That slab will cure for about 28 days. The heat is what makes it get hard. We can pour a bridge in November and cover it with insulated blankets, and at 20*F, the conc will still be 80*F.
A lot of times a big slab will be poured in sections, usually as long/wide as the screed. But doing it that way requires a lot of laborers and finishers.
