I have used Luoding cement floor beam for two years, and the side of the floor beam can be crushed into powder with a hammer, and the surface is not firm.

Try to pour it once. As you said, there is no way. You can also leave the construction joint in the place with the least stress and in the vertical plane. Before pouring new concrete the next day, we should deal with the construction: first remove the loose concrete on the surface, brush a layer of plain cement slurry, and then pour concrete.