We had serious trouble finishing a floor in a basement room where there was no ventilation but the temperature was 80 degrees F. The surface began to harden before bleed water disappeared and we could not finish the floor without working some of the water back into it What can be done to avoid this problem?
The ACI 302 Recommended Practice for Concrete Floor and Slab Construction suggests dragging a loop of heavy garden hose over the surface to remove the water, while disturbing the surface as little as possible. Another method is to "trowel squeegee" the surface by making large sweeps with a long trowel tipped on edge, and using only one trowel stroke in any one area so that water isn't worked into the surface. The next step is to apply a mixture of one part by volume of portland cement and one part of clean medium-to-coarse concrete sand. Cement alone, or cement mixed with fine sand, should not be used. The mixture should be broadcast in two directions at right angles to one another. The first application should be floated into the surface, preferably with a power float, the remainder would then be broadcast and floated in. It should be possible to begin troweling immediately.