Pan floating significantly increases floor flatness and improves finishing productivity, but can it also cause floor imperfections? Section 11.7 of ACI 302.1R-96, "Guide for Concrete Floor and Slab Construction," lists several steps needed to avoid blistering (and presumably delaminations) of floor surfaces. One such step is to avoid using pans for initial machine floating. This seems to imply that initial floating with pans can cause blistering or delaminations. However, there's disagreement on the role played by pan floating when delaminations occur.
Concrete Construction asked Mauro Scali, a petrography consultant with Simpson, Gumpertz and Heger, Arlington, Mass., and Bruce Suprenant, vice president engineering and technical services, Baker Concrete Construction, Monroe, Ohio, to discuss the issue. They both have studied the causes of delamination.