Concrete Technology Mid - I, September - 2014

1.The smallest particle may have a size of about in fineness of cement is
  • 1.5 microns
  • 3.00microns
  • 10 microns
  • 25 microns
Answer: A
2.The size of the cube mould for compressive strength of cement is
  • 7.02 X 7.02 cm
  • 7.04 X 7.04 cm
  • 7.05 X 7.05 cm
  • 7.06 X 7.06 cm
Answer: D
3.The optimum air content in concrete is
  • 1.5 - 2.00 %
  • 2.00 - 2.50%
  • 2.50 - 3.00%
  • 3.00 - 3.50%
Answer: C
4.Silicon dioxide percent present by mass min as per IS 3812-P-I-2003 is
  • 5%
  • 10%
  • 15%
  • 20%
Answer: D
5.The crushing value of aggregate is restricted for concrete used for roads is
  • 10%
  • 15%
  • 20%
  • 30%
Answer: D
6.The percentage of bulking of aggregate is
  • {h1 – h2}/h2 X100
  • {h2 – h1}/h2 X 100
  • {h2- h1}/h1 X 100
  • {h1 – h2}/h1 X 100
Answer: A
7.Maximum size of aggregate for concrete is about
  • 50 mm
  • 75 mm
  • 100 mm
  • 150 mm
Answer: D
8.Most important factor that affects the workability of the concrete is
  • shape
  • surface texture
  • use of admixtures
  • grading
Answer: C
9.The top diameter ,height and bottom diameter of slump cone is respectively
  • 20 cm, 10 cm, 30 cm
  • 30 cm, 20cm, 10cm
  • 20cm, 30cm,10cm
  • 10cm, 30cm, 20cm
Answer: D
10.The separation of constituent of material of concrete is termed as
  • bleeding
  • segregation
  • setting
  • hardening
Answer: B
11.The reaction of cement with water is ___________________ and the reaction liberates
Answer: exothermic,considerable quantity of heat
12.specific surface of cement for 53 grade opc as per IS 12269-1987hould not be less than _____________
Answer: 225 m2/kg
13.High degree of work ability is required in situations like ____________________
Answer: deep beams,thin walls
14.The use of super plasticizers was developed in _______________ and __________ countries.
Answer: japan, germany
15.The elongation index is not applicable to sizes smaller than _____________________
Answer: 6.3 mm
16.Average value of linear thermal coefficient of expansion of concrete may be taken as _______________
Answer: 9.9 x 10-6/ ºC
17.Fineness modulus of coarse sand is in between ____________________
Answer: 2.90 - 3.20
18.For medium degree of workability recommended slump as per IS 456-2000 is _____________________
Answer: 50 - 100mm
19.The stripping time for props to slabs spanning upto 4.5 m is _____________________
Answer: 7 days
20.As per is 1791-1985 concrete mixtures are designates by _______________________.
Answer: Number represents both capacity