17.5.7. Step 7: Trial Mixes and Adjustments

Try these first

1. 1.

   What is a trial mix?

   Hint

   Think about why we prepare a batch before the final mix.

2. 2.

   Why is flexural strength important?

   Hint

   Consider what happens when concrete is loaded.

3. 3.

   What is the first action to take after conducting trial mix tests?

   • Adjust the mix
   • Document the results
   • Prepare another trial

   Hint

   Think about which step ensures we can replicate success.

4. 4.

   True or False: Only flexural strength is important in trial mixes.

   • True
   • False

   Hint

   Recall the tests we conduct on trial mixes.

5. 5.

   A trial mix resulted in a flexural strength of only 3 MPa when the target was 4.5 MPa. Outline the steps you would take to adjust the mix to achieve the desired strength.

   Hint

   Look at each element of the mix and think about how changing each could impact strength.

6. 6.

   You have recorded that a batch has too much workability but passes flexural strength tests. How would you adjust the mix to find a balance?

   Hint

   Identify components that enhance workability and consider their impacts when adjusting.