Really, the concrete plant is on site so the pour shouldn't be constrained by time. I mean they shouldn't run into a traffic jam, right? If the distance is too far from the plant to the pour, simply delay the addition of water until they are closer to the pump site. I'm not any kind of expert, and I'm not there, but from the outside looking in, it seems someone was asleep that day.
Got to care about what you’re doing.
Fixed it.