Concrete Technology Multiple Choice Questions on “Factors Affecting PIC, Cold Weather Concreting”.
1. The moisture content of the aggregate shall not exceed from ____________
a) .1% – .5%
b) 1% – 55
c) 10% – 50%
d) 15%
Answer: a
Clarification: It was recommend by the scientist later on that the moisture content of the aggregates shall not exceed from .1% to .5%.
2. Which one is not the polymeric resin?
a) Polyester resin
b) Epoxy resin
c) Vinyl ester resin
d) Sulphates
Answer: d
Clarification: Polymeric resins that are commonly used in polymer concrete are methacrylate, polyester resin, epoxy resin, vinyl ester resin, and furan resins.
3. Higher resin dosage is recommended when using ________
a) Coarse aggregate
b) Fine aggregates
c) All in one aggregates
d) More cement
Answer: b
Clarification: Higher resin dosage is recommended when using fine aggregate, because of the presence of the large surface area of the materials.
4. Steel fibers helps in the enhancement of its properties.
a) True
b) False
Answer: a
Clarification: Steel fibers, glass fibers, carbon fibers, and polyester fibers have been added to in PIC for enhancement of its properties.
5. The addition of glass fibers are in the range of __________
a) 0-6%
b) 10%
c) 15-20%
d) 20%-25%
Answer: a
Clarification: Most of the studies have reported the addition of glass fibers are in the range of 0-6% in PIC.
6. Concrete is not recommended to be placed at a temperature below __________oC.
a) 2
b) 3
c) 4
d) 5
Answer: d
Clarification: Any concreting operation done at a temperature below 5oC is termed as cold weather concreting.
7. IS: 7861 part-2 deals with __________
a) Hot weathering concrete
b) Cold weathering concrete
c) Air entertained concrete
d) OPC
Answer: b
Clarification: IS: 7861 part-1 deals with hot weather concreting and Part-2 deals with cold weather concreting.
8. Why the time period for removal of form work has to be increased.
a) The development of strength of concrete is retarded compared with development at normal temperature
b) The development of strength of concrete is accelerate compared with development at normal temperature
c) The development of strength of concrete is advanced compared with development at normal temperature
d) The development of strength of concrete is precocious compared with development at normal temperature
Answer: a
Clarification: When the temperature is falling to about 50C or below, the development of strength of concrete is retarded compared with development at normal temperature. Thus, the time period for removal of form work has to be increased.
9. If concrete is exposed to repeated freezing and thawing after the final set, the final qualities of the concrete may also be __________
a) Impair
b) Aid
c) Improve
d) Extend
Answer: a
Clarification: If concrete is exposed to repeated freezing and thawing after the final set and during the hardening period, the final qualities of the concrete may also be impaired.
10. Large temperature differentials within the concrete member may promote __________
a) Elastic shrinkage
b) Cracking
c) High workability
d) Good strength