Question: What is the main advantage of using fly ash as a partial replacement for cement?

Options:

1. Increases the weight of concrete
2. Improves workability and reduces permeability
3. Decreases the setting time
4. Increases the cost of concrete

Correct Answer: Improves workability and reduces permeability

Solution:

Fly ash improves workability, reduces permeability, and can enhance the long-term strength of concrete when used as a partial replacement for cement.