Freeze Thaw

Question 1

6 factors for freeze thaw attack

Answer 1

Aggregates
Cement combinations
Admixtures
Ait void system
Non - air entrained concrete
Air entrained concrete

Question 2

Features of freeze thaw attack (4)

Answer 2

Surface scaling
Internal damage
Pop outs
D - cracking

Question 3

What test is used for aggregates in freeze thaw attack

Answer 3

Soundness test - for water absorption

Question 4

What aggregates give poor performance in freeze thaw attack

Answer 4

White flints and chalk

Question 5

What cement combinations are good for preventing freeze thaw attack (4)

Answer 5

Silica fume
Fly ash no more than 25%
Air entrainment
GGBS no more than 35%

Question 6

What cement combinations are bad for freeze thaw attack (1)

Answer 6

PC

Question 7

What should the air content be to prevent freeze thaw attack

Answer 7

4-6%

Question 8

Best way to control freeze thaw attack

Answer 8

Control water runoff and prevent water ingress - maintanence

Question 9

Does non air entrained concrete have higher or lower strength?

Answer 9

Higher

Question 10

Features of non air entrained concrete

Answer 10

Large air bubbles
Dense microstructure
Low w/s
Silica fume

Question 11

Features of air entrained concrete

Answer 11

Small air bubbles
Provides hydraulic pressure relief for freezing moisture
Spacing factor < 0.2mm to keep bubbles stable