Concrete Moisture Migration Flashcards
1
Q
forces of adhesion, surface tension, cohesion
A
capillary action:
2
Q
moves from areas of high pressure to area of low pressure by diffusion
A
water vapor
3
Q
diffusion
A
water changes from a liquid to a vapor as it evaporates
4
Q
water not used in curing process
A
free water
5
Q
scheduling construction so full cure time, before sealing/floor finishes.
ideally min:
A
6 weeks
6
Q
vapor barrier placement:
A
directly below slab, top of sand/subbase
7
Q
max recommended water-cement (w/c) ratio
A
0.45-.50
8
Q
vapor barrier material
A
thin sheet material, typ. plastic
> 10 mils thick
9
Q
vapor barrier permeance
A
not > 0.04 perm
10
Q
*perm =
A
passage 1 grain water vapor per hour through 1sqft of material @ pressure differential of 1” mercury between the 2 sides of material.
11
Q
only SLOWS rate of vapor transmission
A
Vapor retarder
