High carbon content in the steel causes
Decrease in tensile strength but increase in ductility
Increase in tensile strength but decrease in ductility
Decrease in both tensile strength and ductility
Increase in both tensile strength and ductility
Correct Answer :
B. Increase in tensile strength but decrease in ductility
Related Questions
Pick up the incorrect statement from the following. For performing compressive strength test of cement
Cement and standard sand mortar are used in the ratio of 1 : 3
Water is added at the rate of (P/4) + 3.0 percentage of water where P is the percentage of water for standard consistency
A cube mould of 10 cm × 10 cm × 10 cm is used
The prepared moulds are kept in a atmosphere of 50% relative humidity
Shrinkage in concrete can be reduced by using
Low water cement ratio
Less cement in the concrete
Proper concrete mix
All the above
A concrete having a slump of 6.5 cm, is said to be
Dry
Earth moist
Semi-plastic
Plastic
If the storey height is equal to length of RCC wall, the percentage increase in strength is
0
10
20
30
Diagonal tension in a beam
Is maximum at neutral axis
Decreases below the neutral axis and increases above the neutral axis
Increases below the neutral axis and decreases above the neutral axis
Remains same
Addition of pozzolana to ordinary port land cement, causes
Decrease in early strength
Reduction in chemical action with sulphates
Increase in shrinkage
All the above
Which of the following R.C. retaining walls is suitable for heights beyond 6 m?
L-shaped wall
T-shaped wall
Counterfort type
All of the above
To obtain a very high strength concrete, use very fine grained
Granite
Magnetite
Barite
Volcanic scoria
Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is
30 %
40 %
50 %
60 %
Maximum distance between expansion joints in structures as per IS: 456 1978 is
20 m
30 m
45 m
60 m
Minimum thickness of load bearing RCC wall should be
50 mm
100 mm
150 mm
200 mm
For an ordinary Portland cement
Residual does not exceed 10% when sieved through IS Sieve No. 9
Soundness varies from 5 to 10 mm
Initial setting time is not less than 30 minutes
Compressive stress after 7 days, is not less than 175 kg/cm2
Modulus of elasticity of steel as per IS: 4561978 shall be taken as
20 kN/cm²
200 kN/cm²
200 kN/mm²
2 × 106 N/cm²
The most useless aggregate is one whose surface texture is
Smooth
Granular
Glassy
Honey combed and porous
An aggregate is known as cyclopean aggregate if its size is more than
4.75 mm
30 mm
60 mm
75 mm
As compared to ordinary Portland cement, high alumina cement has
Higher initial setting time but lower final setting time
Lower initial setting time but higher final setting time
Higher initial and final setting times
Lower initial and final setting times
If P, Y and Z are the weights of cement, fine aggregates and coarse aggregates respectively and W/C is the water cement ratio, the minimum quantity of water to be added to first batch, is obtained by the equation
0.1P + 0.3Y + 0.1Z = W/C × P
0.3P + 0.1Y + 0.01Z = W/C × P
0.4P + 0.2Y + 0.01Z = W/C × P
0.5P + 0.3Y + 0.01Z = W/C × P
Vicat apparatus is used for
Fineness test
Consistency test
Test for setting time
Test for tensile strength
The high strength of rapid hardening cement at early stage, is due to its
Finer grinding
Burning at high temperature
Increased lime cement
Higher content of tricalcium
The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds
5 kg/cm2
8 kg/cm2
10 kg/cm2
15 kg/cm2
If the size of panel in a flat slab is 6 m × 6 m, then as per Indian Standard Code, the widths of column strip and middle strip are
3.0 m and 1.5 m
1.5 m and 3.0 m
3.0 m and 3.0 m
1.5 m and 1.5 m
Particles of 0.002 mm size are that of
Clay
Sand
Gravel
None of these
For ensuring quality of concrete, use
Single sized aggregates
Two sized aggregate
Graded aggregates
Coarse aggregates
Gypsum is added for
Colour
Strength
Controlling setting time
None of these
The operation of removing humps and hollows of uniform concrete surface, is known as
Floating
Screeding
Trowelling
Finishing
'Ware house pack' of cement means
Full capacity of the ware house
Pressure exertion of the bags of upper layers
Pressure compaction of the bags on lower layers
Packing the ware house
For concreting tunnel linings, transportation of concrete is done by
Pans
Wheel borrows
Containers
Pumps
Workability improved by adding
Air-entraining agent
Foaming agent
Oily-agent
All the above
Le-Chatelier's apparatus is used for testing
Soundness of cement
Hardness of cement
Strength of cement
Durability of cement
Concrete gains strength due to
Chemical reaction of cement with sand and coarse aggregates
Evaporation of water from concrete
Hydration of cement
All the above