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