Places Concrete Review Questions
Review Questions
- The compressive strength of unreinforced concrete shall not be less than ___ Mpa after 28 days.
a) 10
b) 12
c) 15
d) 18
- When concrete is used for garage and carport floor and exterior steps with a 0.45 water to cement ratio and aggregates of sufficient strength, it shall have a minimum compressive strength of ___ Mpa after 28 days and shall have air entrainment of ___ to ___ percent.
a) 32, 5-8
b) 18, 4-6
c) 16, 3-5
d) 14, 2-4
- Concrete shall be kept at a temperature of not less than ___ °c for 72 hours after placing.
a) 5
b) 10
c) 15
d) 20
- Concrete for exterior steps with a 0.45 water to cement ratio and aggregates of sufficient strength must have a minimum compressive strength of ___ after 28 days and shall have air-entrainment of ___% to ___%.
- In table 9.3.1.7 in the NBC:
- What is the maximum size of aggregate allowed?
- 2 – 40 kg bags of cement contain ____ L.
- The concrete mix is measured by _____ (weight or volume)
- What effect will dirty aggregates have on the strength of concrete?
- The maximum size of aggregates should not exceed:
- Why is more water added to concrete than what is needed for proper hydration?
- List six admixtures and their purpose.
- Calcium chloride should not be used in certain situations, such as:
- Give some reasons for using flyash in a concrete mix
- High strength concrete refers to concrete that has an Mpa rating of _____.
- In high strength concrete it is found that maximum aggregate size ranging from ___ to ___ provide excellent strength characteristics.