Consider the following statements:
The effect of an air entrainment in concrete is to
1. Improve Workability
2. Improve Strength
3. Decrease strength
4. Increase resistance to freezing and thawing
Select which of these is/are correct?
1
1, 2 & 3
2
1, 3 & 4
3
1 & 2
4
1, 2 & 4