4. Shrinkage in Hardened Concrete

Try these first

1. 1.

   Define plastic shrinkage.

   Hint

   Think about how weather can impact newly poured concrete.

2. 2.

   What is the water-cement ratio?

   Hint

   Consider how changing the amount of water would affect the concrete mixture.

3. 3.

   What causes plastic shrinkage in concrete?

   • A) Water content
   • B) Rapid evaporation of surface water
   • C) Chemical reactions within concrete

   Hint

   Think about what happens to water that’s left out in the sun.

4. 4.

   True or False: Drying shrinkage is the most common type of shrinkage in concrete.

   • True
   • False

   Hint

   Think about when concrete loses moisture after setting.

5. 5.

   A concrete slab cracks after drying despite having a low water-cement ratio. What other factors might contribute to this shrinkage, and how could they be addressed?

   Hint

   Consider environmental impacts and construction practices.

6. 6.

   Design a mix that minimizes both plastic and drying shrinkage for a major concrete structure exposed to harsh conditions.

   Hint

   Think about how the right ingredients create a balanced and stable mix.