Concrete Moisture Migration Flashcards Preview

BD_Ballast > Concrete Moisture Migration > Flashcards

Flashcards in Concrete Moisture Migration Deck (11)
Loading 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