Evaporation retarder
A sprayed film applied to fresh concrete between finishing passes to temporarily block moisture loss. It is not a curing compound and is not a finishing aid.
What does evaporation retarder mean?
The product forms a monomolecular film that suppresses evaporation while the concrete is still plastic, protecting against plastic shrinkage cracking during the vulnerable window before curing begins. It is designed to be worked into the surface during the next finishing pass. It is widely misused as a finishing lubricant, which effectively means adding water to the surface and produces the same weak, dusty top layer.
In practice
Crews spraying it and then troweling the diluted paste around are creating exactly the surface defect they were trying to avoid.