17.5.6. Step 6: Mix Calculations (Trial Mixes)

Try these first

1. 1.

   Define what a trial mix is.

   Hint

   Think about testing a small sample before the main batch.

2. 2.

   What is flexural strength?

   Hint

   Consider how a beam would act under a load.

3. 3.

   What is the primary purpose of conducting trial mixes?

   • To finalize the mix design
   • To adjust ingredient proportions
   • To calculate costs

   Hint

   Think about why we test before producing the final mix.

4. 4.

   True or False: Flexural strength is not a significant consideration in pavement design.

   • True
   • False

   Hint

   Remember the role of flexural strength in supporting weight.

5. 5.

   A trial mix resulted in a flexural strength of 3.5 MPa, whereas the target is 5.0 MPa. Suggest a plan to adjust the mix to achieve this target.

   Hint

   Consider how altering these two factors could influence the output.

6. 6.

   During a durability test, a concrete mix shows failure under freeze-thaw cycles. What adjustments would you recommend for future mixes?

   Hint

   What types of admixtures can help improve durability in harsh environments?