For concreting tunnel linings, transportation of concrete is done by
Pans
Wheel borrows
Containers
Pumps
Correct Answer :
D. Pumps
Related Questions
Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is
30 %
40 %
50 %
60 %
Workability of concrete for a given water content is good if the aggregates, are
Rounded aggregate
Irregular aggregate
Angular aggregate
Flaky aggregates
The load factors for live load and dead load are taken respectively as
1.5 and 2.2
2.2 and 1.5
1.5 and 1.5
2.2 and 2.2
Stress strain curve of high tensile steel
Has a definite yield point
Does not show definite yield point but yield point is defined by 0.1% proof stress
Does not show definite yield point but yield point is defined by 0.2% proof stress
Does not show definite yield point but yield point is defined by 2% proof stress,
The ratio of various ingredients (cement, sand, aggregates) in concrete of grade M 200, is
1 : 2 : 4
1 : 3 : 6
1 : 1 ½ : 3
1 : 1 : 2
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
The operation of removing humps and hollows of uniform concrete surface, is known as
Floating
Screeding
Trowelling
Finishing
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
Separation of coarse aggregates from mortar during transportation, is known
Bleeding
Creeping
Segregation
Shrinkage
The strength of concrete after one year as compared to 28 days strength is about
10 to 15% more
15 to 20% more
20 to 25% more
25 to 50% more
For the construction of R.C.C. slabs, columns, beams, walls, etc. the grade of concrete mix used, is
1 : 3 : 6
1 : 1 ½ : 3
1 : 2 : 4
1 : 1 : 2
The maximum percentage of chemical ingredient of cement is that of
Magnesium oxide
Iron oxide
Silica
Lime
'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
The process of mixing, transporting, placing and compacting concrete using Ordinary Port land Cement should not take more than
30 minutes
40 minutes
60 minutes
90 minutes
Pre-stress loss due to friction occurs
Only in post-tensioned beams
Only in pre-tensioned beams
In both post-tensioned and pre-tensioned beams
None of the above
For a longitudinal reinforcing bar in a column, the minimum cover shall neither be less than the diameter of bar nor less than
15 mm
25 mm
30 mm
40 mm
The process of hardening the concrete by keeping its surface moist is known
Placing
Wetting
Curing
Compacting
Segregation is responsible for
Honey-combed concrete
Porous layers in concrete
Surface scaling in concrete
All the above
An ordinary Portland cement when tested for its fineness, should not leave any residue on I.S. sieve No. 9, more than
5 %
10 %
15 %
20 %
A beam curved in plan is designed for
Bending moment and shear
Bending moment and torsion
Shear and torsion
Bending moment, shear and torsion
Concrete containing
Siliceous aggregates, has higher co-efficient of expansion
Igneous aggregates, has intermediate coefficient of expansion
Lime stones, has lowest co-efficient of expansion
All the above
Addition of pozzolana to cement
Decreases workability
Increases strength
Increases heat of hydration
None of these
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
Pick up the incorrect statement from the following:
In properly graded aggregates, bulk density is more
In single size aggregates, bulk density is least
In single size aggregates, bulk density is maximum
None of these
1% of voids in a concrete mix would reduce its strength by about
5 %
10 %
15 %
20 %
Pick up the correct statement from the following:
A highly absorptive aggregate reduces the workability of concrete considerably
The specific gravity of aggregate is important for the determination of the moisture content
The absorption and porosity of an aggregate influence the property of the concrete
All the above
If a beam fails in bond, then its bond strength can be increased most economically by
Increasing the depth of beam
Using thinner bars but more in number
Using thicker bars but less in number
Providing vertical stirrups
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
If the effective working time is 7 hours and per batch time of concrete is 3 minutes, the output of a concrete mixer of 150 litre capacity, is
15,900 litres
16,900 litres
17,900 litres
18,900 litres
The light weight aggregates are obtained from
Sedimentary rocks
Metamorphic rocks
Igneous rocks
Volcanic source