71. The coarse sand has fineness modulus in the range of
- 2.2-2.4
- 2.4-2.6
- 2.6-2.9
- 2.9-3.2
72. Which is the correct order for the given materials (samples 10 cm in height) in terms of their specific strength?
Concrete (25 MPa strength for 10 cm cube; Density 2.40 gm/cm3)
Steel (250 MPa strength for 5 cm dia tube, 5 mm thickness; Density 7.85 gm/cm3)
Bamboo (30 MPa strength for 5 cm dia pole, 5 mm thickness; Density 0.80 gm/cm3)
Wood (20 MPa strength for 10 cm cube; Density 0.70 gm/cm3)
- Concrete > Steel > Bamboo > Wood
- Steel > Concrete > Wood > Bamboo
- Steel > Bamboo > Wood > Concrete
- Steel > Bamboo > Concrete > Wood
73. Aerated concrete is produced by addition of
- copper sulphate
- aluminium powder
- sodium silicate
- zinc silicate
74. The rati0 of compressive strength of fully saturated material to that of same material when dry is called
- Load factor
- Compaction factor
- Coefficient of hardness
- Coefficient of softening
75. Concrete mix proportioning guidelines are given by
- IS 875 (Part-1)-1987
- IS 456-2000
- IS 800-2007
- IS 10262-2009
76. The total number of test strength of samples required to constitute an acceptable record for calculation of standard deviation for each grade of concrete shall not be less than
- 30
- 28
- 21
- 15
77. Which of the following impurities in the mixing water is destructive for concrete?
- calcium chloride
- lead nitrate
- alkalies
- algae
78. The property of a mineral by virtue of which it can be cut with a knife is
- Parting
- Sectile
- Malleable
- Ductile
79. What kind of sample is used for tensile testing of mortars?
- Mortar prism
- Mortar cylinder
- Mortar cube
- Mortar briquette
80. Consider the following strength of concrete
- Cube strength
- Cylinder strength
- Split-tensile strength
- Modulus of rupture
The correct sequence in increasing order of the strength is
- iii, iv, ii, i
- iv, iii, ii, i
- iii, iv, i, ii
- iv, iii, i, ii