9.1. Strength of Hardened Concrete

Try these first

1. 1.

   Define compressive strength.

   Hint

   Think about what happens when you push down on concrete.

2. 2.

   What is a typical tensile strength of concrete?

   Hint

   Recall the relationship between tensile and compressive strengths.

3. 3.

   What is the typical range of compressive strength for general construction?

   • 15-60 MPa
   • 60-100 MPa
   • 100-150 MPa

   Hint

   Recall the specific numeric range mentioned.

4. 4.

   Tensile strength is approximately what percentage of compressive strength?

   • True
   • False

   Hint

   Think about the relationship between the two types of strength.

5. 5.

   Calculate the expected tensile strength of a concrete mixture with a compressive strength of 50 MPa.

   Hint

   Use the provided relationship of tensile to compressive strength.

6. 6.

   Discuss the impacts on the strength of concrete if the water-cement ratio is increased from 0.4 to 0.6.

   Hint

   Consider how extra water changes the concrete structure.