Title:
Concrete Q&A: Streaks in Polished Concrete Slab
Author(s):
Publication:
Concrete International
Volume:
42
Issue:
1
Appears on pages(s):
71-72
Keywords:
DOI:
Date:
1/1/2020
Abstract:
Q. Our company was the concrete subcontractor for
a small slab (5000 ft2 [465 m2]). A second
subcontractor polished the slab after we left the
jobsite. The specification called for a flatness F-number (FF)
of 25, so we placed the slab using a wheel-mounted laserguided
screed. The general contractor didn’t have the slab
measured for F-numbers; however, we’re confident that we
met the specification. We have been notified that the owner
has rejected the slab, citing cream streaks that became visible
during the polishing process. The general contractor is
looking for an answer as to what caused the