12. Trial Mix and Adjustments

Try these first

1. 1.

   What does a trial mix involve?

   Hint

   Consider the key ingredients used.

2. 2.

   Why is the slump test important?

   Hint

   Think about what properties workability affects.

3. 3.

   What is the purpose of a trial mix in concrete design?

   • To randomize concrete composition
   • To assess concrete properties
   • To minimize costs

   Hint

   Consider the implications of testing.

4. 4.

   True or False: A high slump indicates low workability.

   • True
   • False

   Hint

   Think about what a high slump means in practical terms.

5. 5.

   A trial mix results in a slump of 20 mm when the target is 75 mm. Discuss the steps you would take to address this.

   Hint

   Refer back to how workability is influenced in the mixing process.

6. 6.

   You find that the compressive strength of a concrete sample at 28 days is only 22 MPa, while your target is 30 MPa. How would you adjust your mix design?

   Hint

   Think about how strengths can be increased through mix composition.