Building Materials
______________ porcelain contains 70% to 90% silicate of magnesia.
- Cordierite
- Zircon
- Carbon and graphite
- Steatic
Which of the following impurities in the mixing water is destructive for concrete?
- calcium chloride
- lead nitrate
- alkalies
- algae
Which of the following defects is caused by vapourization of entrapped moisture of solvents in a painted surface?
- saponification
- blistering
- blooming
- cissing
To impart plasticity is a main function of which ingredient?
- Silica
- Alumina
- Iron
- MgO
Volume of 1 bag of cement is
- 0.025 cubic meter
- 0.035 cubic meter
- 0.045 cubic meter
- 0.055 cubic meter
Building Materials
The coefficient of thermal expansion of cement concrete
- 3 × 10^(-4) per °C
- 3 × 10^(-5) per °C
- 3 × 10^(-6) per °C
- 3 × 10^(-8) per °C
The Vicat apparatus is used for finding the ______________ cement
- Initial setting time
- Soundness
- Fineness
- Slump value
The range of Mohs scale of hardness is
- 0-10
- 0-14
- 1-10
- 1-14
In cement, following compounds can be used as accelerators except
- CaCl2
- CaSO4
- NaCl
- Na2SO4
Which of the following impurities in the mixing water is having the highest destructive effect for concrete
- Calcium chloride
- Lead nitrate
- Alkalies
- Algae
Building Materials
The nominal thickness of glass available in market ranges in between
- 3.0 – 6.3 mm
- 4.0 – 7.3 mm
- 5.0 – 8.3 mm
- 7.0 – 10.3 mm
The thin radial fibres extending from pith to cambium layer are known as
- Inner Bark
- Outer Bark
- Sap Wood
- Medullary Rays
The concrete mix with slump value between 25 and 75 is considered _ workable.
- Very low
- Low
- Medium
- High
The process of mixing clay, water and other ingredients to make brick is known as
- pugging
- moulding
- drying
- kneading
Ceramics can easily withstand in high temperatures between
- 400 – 550 °C
- 550 – 700 °C
- 700 – 850 °C
- 850 – 1000 °C
Building Materials
M20 grade of concrete has the following proportion of the ingredients of cement, sand and coarse aggregates.
- 1: 2 :4
- 1: 1.5: 3
- 1: 4: 8
- 1:1.25:2.5
The air permeability test is used for finding out _____________.
- Fineness of cement
- Permeability of cement
- Consistency of cement
- Strength of cement
The bulking of sand occurs due to
- air in voids
- moisture in voids
- surface tension
- capillarity action
Which is the correct order for the given materials (samples 10 cm in height) in terms of their specific strength?
(i) Concrete (25 MPa strength for 10 cm cube; Density 2.40 gm/cm³)
(ii) Steel (250 MPa strength for 5 cm dia tube, 5 mm thickness; Density 7.85 gm/cm³)
(iii) Bamboo (30 MPa strength for 5 cm dia pole, 5 mm thickness; Density 0.80 gm/cm³)
(iv) 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
The minimum compressive strength of first class bricks should be
- 5 N/mm²
- 7.5 N/mm²
- 10 N/mm²
- 15 N/mm²
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