Indicate whether the statement is true or false. 1. Aggregate must be clean and
ID: 1844437 • Letter: I
Question
Indicate whether the statement is true or false.
1. Aggregate must be clean and free of dirt, clay, or vegetable matter.
2. The best water for use in mixing concrete contains a small amount of oil to allow it to mix better with the
aggregate.
3. Concrete hardens just as well under water as it does in air.
4. Rapid drying will reduce the strength of concrete.
5. The process of consolidation (often done by using a concrete vibrator) removes air pockets and forces the concrete into all parts of the forms.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
6. What characteristic of concrete is most important to its use in foundations?
a.highly resistant to chemicals
c.high compressive strength
b.can be formed into almost any shape
d.widely available
7. What quality of water is needed for a concrete mix?
a.clean enough to drink
c.spring
b.reasonably clear
d.distilled
8. Ready-mix concrete is the most economical choice if you need _____ or more.
a.2 cubic feet
c.2 cubic yards
b.4 cubic feet
d.4 cubic yards
9. The most common material used for fine aggregate is
a.crushed stone.
c.sand.
b.gravel.
d.wood chips.
10. The appearance of fine cracks that appear in irregular patterns over the surface of the concrete is
a.crazing.
c.chairing.
b.efflorescence.
d.slumping.
Completion
Complete each statement.
11. In really cold weather, the temperature of concrete should be kept above ____________________ until the concrete sets.
12. Instead of rebar, _________________________ fabric can be placed in wet concrete slabs for reinforcement.
13. Both steel and ____________________ fibers can be added to concrete to improve its qualities.
14. In walls the aggregate should be no more than ____________________ of the thickness of the finished wall.
15. A metal tool with a wide, flat blade that is used for shaping and spreading substances such as concrete is a(n) ____________________.
Matching
Match each concrete-related term to its definition listed below.
a.hydration
d.admixture
b.aggregate
e.accelerator
c.Portland cement
16. Any unusual ingredient added to a concrete mix to change its characteristics
17. The granular component of concrete, such as sand or gravel
18. The chemical reaction that occurs when concrete is mixed
19. An ingredient added to concrete to allow it to be put into use quickly
Match each type of cement to its definition listed below.
a.Type I
d.Type IV (low heat)
b.Type II
e.Type V (sulfate-resistant)
c.Type III
20. Standard grade; used for most general concrete construction
21. High-strength; used where concrete forms must be removed quickly
22. Modified grade: used for most general construction purposes; generates less heat during hydration than Type I
23. Prevents cracking caused by temperature changes; used for large projects like dams
Match each word to the correct statement below.
a.anchor
d.mortar
b.self-leveling
e.resurfacing
c.hydraulic
24. Used to repair damaged concrete surfaces, this cement
Explanation / Answer
1)True
2)False
3) False
4) True
5) True
6)c
7)a
8)a
9)sand(c)
10)a
11)surrounding temperature
12)fiber mesh (or) glass fabric
13)Glass
14)onefifth(1/5)
15)trowel
16)d
17)b
18)a
19)e
20)a(Type-I)
21)c(Type-III)
22)e(Type-V)
23)d(Type-IV)
24)e(resurfacing)
25)b(self levelling)