7.7.4. Harsh Mix in RMC Plants

Try these first

1. 1.

   What is a harsh mix?

   Hint

   Think about the characteristics of the mix.

2. 2.

   Name one cause of a harsh mix.

   Hint

   Consider the types of aggregates in the mix.

3. 3.

   What is the main cause of a harsh mix in RMC plants?

   • Insufficient fines
   • Too much water
   • High ambient temperature

   Hint

   Think about what helps to make the mix smooth.

4. 4.

   True or False: A harsher mix can improve the strength of the final concrete structure.

   • True
   • False

   Hint

   Consider how workability affects the concrete application.

5. 5.

   Calculate the optimal fine to coarse aggregate ratio to mitigate harshness in a mix. Given: 30% maximum coarse aggregate size and current fine aggregates at 20%.

   Hint

   Think about what ratio usually works best for concrete and adjust accordingly.

6. 6.

   Case Study: During a site evaluation, a harsh mix was discovered causing placement issues. Suggest a step-by-step approach to resolve this, including material adjustments.

   Hint

   Consider what the first steps in resolving a construction issue might involve.