Civil engineer objective questions – Concrete Technology (Section-4)

26. Slag cement is used is

a) dam                                                  

b) abutment 

c) RCC                                                   

d) none of the above

27. Pick up the correct statement from the following:

a) insufficient quantity of water makes the concrete mix harsh 

b) insufficient quantity of water makes the concrete unworkable

c) excess quantity of water makes the concrete segregated

d) excess quantity of water cause bleeding in concrete

e) all of the above

28. Pick up the incorrect statement from the following: 

a) Tricalcium silicate (C3S) hydrates rapidly

b) Tricalcium silicate (C3S) generates more heat of hydration

c) Tricalcium silicate (C3S) develops early strength 

d) Tricalcium silicate (C3S) has more resistance to sulphate

attack

29. Di-calcium silicate (C₂S) 

a) hydrates rapidly

b) generates less heat of hydration

c) hardens rapidly

d) provides bad ultimate strength to cement

30. Tri-calcium aluminate (C3A)

a) reacts fast with water

b) generates max heat of hydration

c) hardness rapidly

d) provides bad ultimate strength to cement

31. Pick up the correct statement from the following:

a) high percentage of C3S and low percentage of C₂S cause rapid hardening 

b) high percentage of C3S and low percentage of C₂S make the cement less resistive to chemical attack

c) low percentage of C3S and high percentage of C₂Scontribute to slow hardening 

d) low percentage of C3S and high percentage of C₂S provide greater resistance to chemical attack

e) all of the above

32.Pick up the incorrect statement from the following: 

a) the degree of grading of cement, is called fineness

b) the process of changing cement paste into hard mass, is known as setting of cement

c) the phenomenon by virtue of which cement does not allow transmission of sound, is known as soundness of cement 

d) the heat generated during chemical reaction of cement with water, is known as heat of hydration

33. When water is added to cement

a) heat is generated 

b) heat is absorbed

c) chemical reaction is absorbed 

d) impurities are washed out

34. The development of strength of cement and its fineness are 

a) directly proportional                              

b) inversely proportional

c) randomly related                                    

d) not related

35. The increase in the strength of concrete with time is 

a) linear                                                        

b) non-linear

c) asymptotic                                                

d) all of the above

36. For ordinary portland cement 

a) residual does not exceed 10% when sieved through IS sieve No. 9

b) soundness varies from 5 to 10

c) initial setting time is not less than 30 minutes

d) compressive stress after 7 days, is not less than 175kg/cm² 

e) all of the above 

37. The initial and final setting times of ordinary Portland cement are approximately related are

a) T = 540 + t                                                

b) T = 270+t     

c) T = 90+1.2t                                               

d) T = 90+ t

Where T and t are final and initial setting time.

38. Hydration of cement is due to chemical action of water with

a) tricalcium silicate and dicalcium silicate

b) dicalcium silicate and tricalcium aluminate 

c) tricalcium aluminate and tricalcium alumino ferrite

d) all of the above

39. Hardening of cement occurs at

a) rapid rate during the first few days and afterwards it continues to increase at a decreased rate

b) slow rate during the first few days and afterwards it continues to increase at a rapid rate 

c) uniform rate throughout its age

d) none of the above

40. Density of ordinary portland cement is

a) 1.2-1.4t/m³                                            

b) 1.4-1.5t/m³ 

c) 1-5-1.6t/m³                                            

d) none of the above

41. The high strength of rapid hardening cement at early stage, is due to

a) finer grinding

b) burning at high temperature

c) increased lime cement 

d) higher content of tricalcium

42. For road pavements, the cement generally used, is

a) ordinary portland cement 

b) rapid hardening cement

c) low heat cement

d) blast furnace slag cement

43. You are asked to construct a massive dam, the type of cement you will use, is

a) ordinary portland cement 

b) rapid hardening cement

c) low heat cement

d) blast furnace slag cement

44. The commercial name of white and coloured cement in India, is

a) colocrete

b) rainbow cement

c) silvicrete, snowcem

d) all of the above

45. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is

a) 30%                                                           

b) 40%

c) 50%                                                           

d) 60%

46. Pick up the correct statement from the following:

a) calcium chloride acts as a retarder 

b) gypsum (calcium sulphate) acts as an accelerator

c) gypsum (calcium sulphate) acts as a retarder 

d) calcium chloride acts as an accelerator

e) both (c) and (d) of above

47. For the construction of thin R.C.C. structure, the type of

cement to be avoided, is 

a) ordinary portland cement

b) rapid hardening cement

c) low heat cement

d) blast furnace slag cement

48. Sand generally contains salt if it is obtained from

a) nala beds                                        

b) river beds

c) sea beds                                          

d) all of the above

49. The presence of common salt in sand results in

a) corrosion of reinf

b) scaling

c) pitting

d) all of the above

50. Bulking of sand is

a) mixing of different sizes of sand particles 

b) mixing of lime with sand

c) mixing water with sand

d) swelling of sand when wetted