The cement whose strength is a little lower than the ordinary cement during the first three months but attains afterwards the same strength, is known as
Low-heat Portland cement
Rapid hardening Portland cement
Portland blast slag cement
Portland pozzolana cement
Correct Answer :
A. Low-heat Portland cement
Related Questions
To obtain a very high strength concrete, use very fine grained
Granite
Magnetite
Barite
Volcanic scoria
Maximum distance between expansion joints in structures as per IS: 456 1978 is
20 m
30 m
45 m
60 m
For preparing ordinary concrete, the quantity of water used, is
5% by weight of aggregates plus 20% of weight of cement
10% by weight of aggregates plus 10% of weight of cement
5% by weight of aggregates plus 30% of weight of cement
30% by weight of aggregates plus 10% of weight of cement
The datum temperature for maturity by Plowman, is
23°C
0°
- 5.6°C
- 11.7°C
An excess of flaky particles in concrete aggregates
Decreases the workability
Increases the quantity of water and sand
More than 15% are not desirable
All the above
Pick up the incorrect statement applicable to the field test of good cement.
When one thrusts one's hand into a bag of cement, one should feel warm
The colour of the cement is bluish
By rubbing cement in between fingers, one should feed rough
All the above
In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for
20 times
25 times
30 times
50 times
The final operation of finishing floors, is known as
Screeding
Floating
Trowelling
Finishing
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
If the slump of a concrete mix is 60 mm, its workability is
Very low
Low
Medium
High
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
Normally pre-stressing wires are arranged in the
Upper part of the beam
Lower part of the beam
Center
Anywhere
Vicat apparatus is used for
Fineness test
Consistency test
Test for setting time
Test for tensile strength
Permissible compressive strength of M 300 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
300 kg/cm2
The grade of concrete not recommended by I.S. : 456, is
M 100
M 200
M 300
M 500
The entrained air in concrete
Increases workability
Decreases workability
Decreases resistance to weathering
Increases strength
Sinking of an intermediate support of a continuous beam (i) Reduces the negative moment at support (ii) Increases the negative moment at support (iii) Reduces the positive moment at center of span (iv) Increases the positive moment at center of span The correct answer is
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
In a pile of length l, the points of suspension from ends for lifting it are located at
0.207 l
0.25 l
0.293 l
0.333 l
The type of aggregates not suitable for high strength concrete and for pavements subjected to tension, is
Rounded aggregate
Irregular aggregate
Angular aggregate
Flaky aggregate
Pick up the correct proportions of chemical ingredients of cement
Lime : Silica : Alumina : Iron oxide : 63 : 22 : 6 : 3
Silica : Lime : Alumina : Iron oxide : 63 : 22 : 6 : 3
Alumina : Silica : Lime : Iron oxide : 63 : 22 : 6 : 3
Iron oxide : Alumina : Silica : Lime : 63 : 22 : 6 : 3
The minimum cover to the ties or spirals should not be less than
15 mm
20 mm
25 mm
50 mm
Cube strength of controlled concrete to be used for pre-tensioned and post-tensioned work respectively should not be less than
35 MPa and 42 MPa
42 MPa and 35 MPa
42 MPa and 53 MPa
53 MPa and 42 MPa
Curing a concrete for long period ensures better
Volume stability
Strength
Water resistance
All the above
The surface where two successive placements of concrete meet, is known as
Contraction joint
Expansion joint
Construction joint
Both (a) and (b)
Pick up the correct statement from the following:
Sand stones may be divided into calcareous, siliceous and ferruginous sand stones
Concrete using sand stones, cracks due to excessive shrinkage
Broken bricks produce a concrete having good fire resisting qualities
All the above
The compaction of concrete, improves
Density
Strength
Durability
All the above
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
For quality control of Portland cement, the test essentially done is
Setting time
Tensile strength
Consistency
All the above
Joints in concrete structures, are provided
To reduce the tensile stresses likely to be developed due to evaporation of water
To minimise the change in the dimensions of the slab
To minimise the necessary cracking
All the above
Slump test is done for
Clay
Sand
Lime
Concrete