18.1. Principles of Concrete Mix Design

Try these first

1. 1.

   Define workability in the context of concrete mix design.

   Hint

   Think about why a concrete mix needs to be easy to handle.

2. 2.

   What does the characteristic strength (fck) represent?

   Hint

   Recall the importance of time in concrete setting.

3. 3.

   What is workability in concrete mix design?

   • The ease of mixing and placing concrete
   • The strength of concrete
   • The cost of concrete

   Hint

   Consider the handling of concrete on a job site.

4. 4.

   True or False: A lower water-cement ratio always leads to better workability.

   • True
   • False

   Hint

   Think about the effects of too little water.

5. 5.

   A construction project requires a high-strength concrete that will be exposed to harsh weather. Identify the key considerations for mix design that prioritize strength and durability.

   Hint

   Think about environmental factors and material selection that impact durability.

6. 6.

   Calculate the target mean strength for a concrete mix if the characteristic strength is 25 MPa and the standard deviation is 4 MPa using k = 1.5.

   Hint

   Use the given formula to incorporate all the variables.