from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A weak layer of cement and aggregate fines on a concrete surface that is usually caused by an overwet mixture, overworking the mixture, improper or excessive finishing or combination thereof. Also, could be caused when a slurry mix is used on a deep foundation, where the slurry mix is not completeley removed before placing concrete on top.
from The Century Dictionary and Cyclopedia
- n. The milky washings from the surface of concrete which has recently been laid under water.
Sorry, no etymologies found.
High-pressure jets of water and compressed air scoured the hardened concrete to rid it of dirt, rocks, and, especially, laitance.
The sperm mass is called white roe, milt, or laitance, and is creamy rather than granular the sperm cells suspended in the proteinaceous fluid are microscopic.
Even in almost still water some of the cement will rise to the surface and appear as a sort of milky scum, commonly called _laitance_.
Mr. Douglas remarks that the back of the block should always be at the top in molding since the laitance or slime always flushes to the surface making a weak skin which will develop hair cracks.