Building Materials (Concrete)

1. Active compounds of cement when reacts with water, cause
(a)        initial setting of cement
(b)        final setting of cement
(c)        contributes little after 24 to 72 hours
(d)        both (a) and (c)

2. The reaction of C3S is responsible for strength development for the
(a)        first 14 days
(b)        first 28 days
(c)        whole life
(d)        first three years

3. The reaction of C2S is responsible for
(a)        earlier strength of concrete
(b)        later strength of concrete
(c)        both (a) and (b)
(d)        neither (a) nor (b)

4. In concrete, compressive strength developed after 28 days is 75% of the
(a)        initial strength
(b)        strength after 3 years
(c)        strength after 5 years
(d)        ultimate strength

5. During hydration, cement gel
(a)        increases in volume
(b)        decreases in volume
(c)        causes segregation
(d)        causes bleeding

6. Reaction product after hydration, consists of
(a)        calcium aluminate
(b)        calcium hydroxide
(c)        calcium silicate
(d)        all these

7. The composition of calcium hydroxide and hydrated calcium silicates, is called
(a)        Portland cement
(b)        high alumina cement
(c)        cement gel
(d)        none of these

8. High alumina cement is produced by fusing together a mixture of
 (a)       limestone and bauxite
(b)        limestone, bauxite and gypsum
(c)        limestone, gypsum and clay
(d)        limestone, gypsum, bauxite and clay      (IES)

9. During hydration, cement gel
(a)        increases in volume
(b)        decreases in volume
(c)        causes segregation
(d)        causes bleeding

10. The total volume occupied by gel after full hydration is
(a)        more than the volume of water and cement before hydration
(b)        less than the volume of water and cement before hydration
(c)        same as the volume of water and cement before hydration
(d)        none of these

Answers
1. d
2. b
3. b
4. d
5. a
6. d
7. c
8. a
9. a
10. c

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