The maximum amount of dust which may be permitted in aggregates is
5% of the total aggregates for low workability with a coarse grading
10% of the total aggregates for low workability with a fine grading
20% of the total aggregates for a mix having high workability with fine grading
All the above
Correct Answer :
D. All the above
Related Questions
The rock which is not calcareous, is:
Lime stone
Chalk
Laterite
None of these
An aggregate which passes through 25 mm I.S. sieve and is retained on 20 mm sieve, is said to be flaky if its least dimension is less than
22.5 mm
18.5 mm
16.5 mm
13.5 mm
The aggregate impact value of the aggregate used in
Building concrete is less than 45
Road pavement concrete is less than 30
Runway concrete is less than 30
All the above
A T-shaped retaining wall mainly consists of
One cantilever
Two cantilevers
Three cantilevers
Four cantilevers
Higher workability of concrete is required if the structure is
Made with cement concrete
Thick and reinforced
Thin and heavily reinforced
Thick and heavily reinforced
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
Maximum percentage reinforcement in case of slabs is limited to
2
4
6
8
During erection, the pile of length l is supported by a crane at a distance of
0.207 l
0.293 l
0.707 l
0.793 l From the driving end of pile which rests on the ground
The ratio of the length to breadth of a wooden float, is
4.5
5.5
6.5
7.5
The percentage of the aggregate of F.M. 2.6 to be combined with coarse aggregate of F.M. 6.8 for obtaining the aggregates of F.M. 5.4, is
30 %
40 %
50 %
60 %
The increased cohesiveness of concrete, makes it
Less liable to segregation
More liable to segregation
More liable to bleeding
More liable for surface scaling in frosty weather
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 maximum percentage of chemical ingredient of cement is that of
Magnesium oxide
Iron oxide
Silica
Lime
The purpose of reinforcement in pre-stressed concrete is
To provide adequate bond stress
To resist tensile stresses
To impart initial compressive stress in concrete
All of the above
According to IS: 4561978, minimum slenderness ratio for a short column is
Less than 12
Less than 18
Between 18 and 24
More than 24
The percentage of reinforcement in case of slabs, when high strength deformed bars are used is not less than
0.15
0.12
0.30
1.00
For ensuring quality of concrete, use
Single sized aggregates
Two sized aggregate
Graded aggregates
Coarse aggregates
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 temperature reinforcement in the vertical slab of a T-shaped R.C. retaining wall is
Not needed
Provided equally on inner and front faces
Provided more on inner face than on front face
Provided more on front face than on inner face
In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on
Front face only
Inner face only
Both front face and inner face
None of the above
To ensure constant moisture content in aggregates
Area of each aggregate pile should be large
Height of each aggregate pile should not exceed 1.50 m
Aggregate pile should be left for 24 hours before aggregates are used
All the above
Tricalcium aluminate (C3A)
Reacts fast with water
Generates less heat of hydration
Causes initial setting and early strength of cement
Does not contribute to develop ultimate strength
Pick up the correct statement from the following:
Insufficient quantity of water makes the concrete mix harsh
Insufficient quantity of water makes the concrete unworkable
Excess quantity of water makes the concrete segregated
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 %
For construction of structures in sea water, the cement generally preferred to, is
Portland-pozzolana cement
Quick setting cement
Low heat Portland cement
Rapid hardening cement
Sand requiring a high water cement ratio, belongs to
Zone I
Zone II
Zone III
Zone IV
Ordinary Portland cement is manufactured from
Lime stone and clay
Gypsum and lime
Pozzolana
Lime, pozzolana and clay
The lower water cement ratio in concrete, introduces
Smaller creep and shrinkage
Greater density and smaller permeability
Improved frost resistance
All the above
For a good concrete
Aggregates should be hard and durable
Water should be free from organic materials
Cement should be sufficient to produce the required strength
All the above
When shear stress exceeds the permissible limit in a slab, then it is reduced by
Increasing the depth
Providing shear reinforcement
Using high strength steel
Using thinner bars but more in number