The top of a dusting floor is weak because it was finished with bleed water on it, dusted with dry cement, poorly cured, frozen early, or carbonated by exhaust from unvented heaters in a cold-weather enclosure. It sheds fine powder under foot and forklift traffic and keeps doing so. Light cases are fixed with silicate densifiers; bad ones need grinding or a topping.
Whole back room is dusting, and the floor guys say the heaters in that tent were never vented.
Also heard as
- dusty slab
- chalking
Related terms
Bleed water
Water that rises to the surface of fresh concrete as the heavier solids settle.
Curing
Keeping fresh concrete moist and warm enough, for long enough, that the cement keeps hydrating.
Cold weather concreting
Placing and protecting concrete when air temperatures are at or expected to drop below 40 F.
Laitance
The soft, chalky skin of fines that bleed water leaves on top of concrete, too weak to bond to.