Building Materials
The approximate ratio between the strengths of cement concrete at 7 days and 28 days is
- 3/4
- 2/3
- 1/2
- 1/3
For complete hydration of cement, the w/c ratio needed is
- less than 0.25
- more than 0.25 but less than 0.35
- more than 0.35 but less than 0.45
- more than 0.45 but less than 0.60
Which of the following is a significant constituent of sedimentary rock ?
- magnetite
- hematite
- calcite
- halite
What is the loading rate used to determine the brick’s compressive strength?
- 14 N/mm² per hour
- 14 N/mm² per minute
- 20 N/mm² per hour
- 20 N/mm² per minute
The slenderness ratio for masonry walls should not be more than
- 10
- 20
- 30
- 40
Building Materials
Sulphate attack on brickwork mortars is principally caused by the reaction between sulphate in solution and the __________________ constituent of Portland cement
- C2S
- C3S
- C3A
- C4AF
Efflorescence of bricks is due to
- Soluble salts present in clay for making bricks
- High porosity of bricks
- High silt content in bricks
- Excessive burning of bricks
Which of the following do not influence the corrosion in steel structures?
i. Carbon dioxide
ii. Chlorides
iii. Oxygen
iv. Water
- Only (i)
- (i) and (ii)
- (i), (ii) and (iii)
- (i), (ii), (iii) and (iv)
Excess of silica makes brick
- brittle on burning
- to crack on drying
- to melt on burning
- to warp
The fineness of cement can be found out by sieve analysis using IS sieve number
- 6
- 9
- 10
- 20
Building Materials
Ultra-High Performance Concrete (UHPC), also known as ______________
- Reactive powder concrete
- NPC
- Active powder concrete
- High Strength concrete
For the purpose of checking the nominal mass of high strength deformed steel bars, the density of steel shall be taken as
- 785 kg/mm² of the cross-sectional area per metre
- 7.85 kg/mm² of the cross-sectional area per metre
- 0.785 kg/mm² of the cross-sectional area per metre
- 0.00785 kg/mm² of the cross-sectional area per metre
Which of the following statement(s) is/are correct with reference to masonry mortars?
(i) Ordinary Portland cement may preferably be used instead of Portland Pozzolana cement where serious sulphate attack is expected
(ii) The rate of hardening of cement mortars is slower than that of lime mortars.
- Only (i)
- Only (ii)
- Both (i) & (ii)
- Neither (i) nor (ii)
Le Chatlier’s method can be used to determine
- Unsoundness of Cement
- Soundness of Cement
- Fineness of aggregate
- Sulphur content
Strength of concrete increases with
- increase in water-cement ratio
- increase in fineness of cement
- decrease in curing time
- none of the above
Building Materials
As specified in IS: 3087, the average modulus of rupture of ‘flat pressed three layer’ of Grade – I pre-laminated particle board is
- 15 N/mm²
- 10 N/mm²
- 12.5 N/mm²
- 11 N/mm²
Which of the following is not a manufactured fine aggregate?
- Iron slag aggregate
- Recycled concrete aggregate
- Bottom ash from Thermal Power Plant
- Crushed sand
The limit of proportionality is applicable more in the case of
- concrete
- mild steel
- wood
- cast iron
If in an application, higher ultimate strength is desired, then which of the cements is most suitable?
- Cement that has a higher C3S content
- Cement that has a higher C2S content
- Cement that has a higher C3A content
- Cement that has very little gypsum
Which of the following stones is the most suitable for roof covering, floorings, damp proofing and partitions?
- Marble
- Granite
- Basalt
- Slate
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