7.4.4. Select Proportions of SCMs

Try these first

1. 1.

   What is silica fume used for in HPC?

   Hint

   Think of its role in improving concrete density.

2. 2.

   Name one SCM that improves workability.

   Hint

   It's a byproduct from burning coal.

3. 3.

   What is the recommended percentage of silica fume in HPC?

   • 0-5%
   • 5-10%
   • 10-15%

   Hint

   It's a small percentage but very powerful in effect.

4. 4.

   True or False: Fly ash can only be used in low-strength concrete.

   • True
   • False

   Hint

   Think about its benefits across different concrete strengths.

5. 5.

   Design a High Performance Concrete mix incorporating 10% silica fume, 20% fly ash, and 30% GGBS. Calculate the total binder content if the total weight of concrete is 800 kg.

   Hint

   Determine the percentages relative to the total weight.

6. 6.

   Discuss the effects on workability and strength if silica fume is increased to 15% in an HPC mix. What adjustments might you make?

   Hint

   Consider how material interactions can change.