Which of the following will NOT prevent cracks resulting from sulphate attack?

Explanation:

1. Sulphate attack occurs when sulphates from the soil or water react with the components of concrete, causing expansion, cracking, and deterioration.

2. Using bricks containing high soluble salts can exacerbate sulphate attack because the salts present in the bricks can leach into the surrounding concrete and further contribute to damage.

3. On the other hand, options like sulphate-resistant cement, rich cement mortar or concrete, and damp proofing are effective methods to mitigate the effects of sulphate attack by either reducing exposure to moisture or using materials that resist chemical reactions.

 Additional InformationMethods of Preventing Sulphate Attack

1. Sulphate-Resistant Cement:

   • Using sulphate-resistant cement (SRC) reduces the risk of sulphate attack. This type of cement has lower levels of tricalcium aluminate (C3A), which is more susceptible to reacting with sulphates.

2. Rich Cement Mortar or Concrete:

   • Using a high cement content (rich concrete) can make the material denser, reducing the permeation of sulphates into the concrete. However, simply increasing the cement content may not be a complete solution.

3. Provision of Damp Proofing:

   • Preventing excessive moisture exposure through damp proofing ensures that sulphates do not come into contact with the concrete in the first place, thus protecting it from chemical reactions.

4. Avoiding High-Salt Materials:

   • Bricks with high soluble salts can contribute to the problem. It’s essential to avoid using materials with high soluble salts in areas prone to sulphate attack. This is why option 1 is incorrect—using high-salt bricks increases the risk of damage.

5. Using Pozzolanic Materials:

   • Materials like fly ash or slag can also improve the concrete’s resistance to sulphate attack because they help reduce the amount of calcium hydroxide in the mix and enhance the density of the concrete.