Choose the Incorrect option with respect to Sulphate attack on Concrete.
1
Magnesium Sulphate has less damaging effect than other sulphates present.
2
The vulnerability of concrete to Sulphate attack can be reduced by the use of cement having low percentage of Tricalcium aluminate.
3
Improved resistance to sulphate attack can be achieved by the use of Portland Pozzolana cement.
4
Concrete attacked by Sulphates has a whitish appearance, with start of damage at the edges and corners, followed by cracking and spalling of concrete.
5
None of these