5. Selection of Water-Cement Ratio

Try these first

1. 1.

   What is the effect of a high water-cement ratio on concrete?

   Hint

   Think about how water affects solidity.

2. 2.

   Name one guideline to determine the water-cement ratio.

   Hint

   Consider the standards governing concrete design.

3. 3.

   What is the primary influence of the water-cement ratio on concrete?

   • Durability
   • Aesthetic
   • Compressive Strength
   • Color

   Hint

   Look for the factor that combines how robust the concrete is.

4. 4.

   True or False: A lower water-cement ratio generally results in higher strength.

   • True
   • False

   Hint

   Think about the relationship between water and solidity.

5. 5.

   Consider a scenario where the required compressive strength of concrete is 30 MPa. The durability requirement suggests a maximum w/c ratio of 0.45. You start trials at 0.50, adjusting down for workability. Describe your findings.

   Hint

   What trends do you notice as you lower the water content?

6. 6.

   You are designing a mix for an area with harsh weather. The requirements state a w/c ratio of 0.40 is needed. However, your initial trials at 0.45 provide a workable mix that barely meets criteria. What steps would you take?

   Hint

   How do additives influence your mix?