Construction joint
A planned stopping point where one placement ends and the next begins, detailed with a keyway or dowels so the two sections still act together.
What does construction joint mean?
Unlike a cold joint, a construction joint is designed into the work, with its location chosen where forces are low and its surface prepared for bond or load transfer. Preparation typically means cleaning laitance off the hardened face and roughening it, plus continuing reinforcement across it where required. Poorly prepared construction joints leak, which is why they matter so much in basement walls and water-holding structures.
In practice
On a wall pour that will take two days, where the crew stops is a joint decision made in advance, not wherever the last truck runs out.