Strength of concrete with passage of time
Increases
Decreases
Fluctuates
Remains constant
Correct Answer :
A. Increases
Related Questions
The average permissible stress in bond for plain bars in tension is
Increased by 10% for bars in compression
Increased by 25% for bars in compression
Decreased by 10% for bars in compression
Decreased by 25% for bars in compression
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
Particles of 0.002 mm size are that of
Clay
Sand
Gravel
None of these
Pick up the correct statement from the following:
The weight of ingredients of concrete mix, is taken in kilograms
Water and aggregates are measured in litres
20 bags of cement make one tonne
All the above
If the permissible stress in steel in tension is 140 N/mm², then the depth of neutral axis for a singly reinforced rectangular balanced section will be
0.35 d
0.40 d
0.45 d
Dependent on grade of concrete also
Pick up the correct statement from the following:
Cement should be mixed for at least one minute
10% of water is placed in the rotating drum before adding dry material
10% of water is added after placing the other ingredients in the drum
All the above
For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be
0.75 - 0.80
0.80 - 0.85
0.85 - 0.92
Above 0.92
The bulk density of aggregates does not depend upon:
Size and shape of aggregates
Specific gravity of aggregates
Grading of aggregates
Size and shape of the container
Pick up the incorrect statement from the following. While performing preliminary test on concrete
Proportions of the material and water should be the same as to be used at the work site
Cement should be mixed by hand in order to maintain uniformity
Concrete mix should be stored in air-tight containers
Concrete ingredients should be kept at a temperature of 37° ± 2°C
The concrete mix which causes difficulty in obtaining a smooth finish, possess
Segregation
Internal friction
Hardness
Bleeding
An aggregate is known as cyclopean aggregate if its size is more than
4.75 mm
30 mm
60 mm
75 mm
Critical section for shear in case of flat slabs is at a distance of
Effective depth of slab from periphery of column/drop panel
d/2 from periphery of column/capital/ drop panel
At the drop panel of slab
At the periphery of column
'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
Pick up the correct statement from the following:
Water cement paste hardens due to hydration
During hardening cement binds the aggregates together
Cement provides strength, durability and water tightness to the concrete
All the above
The following proportion of the ingredients of concrete mix, is not in conformation to arbitrary method of proportioning
1 : 1 : 2
1 : 2 : 4
1 : 3 : 6
1 : 4 : 10
Pick up the correct statement from the following:
The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm
The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm
The material having particles of size varying from 0.06 mm to 0.002 mm, is known as silt
All the above
Too wet concrete may cause
Weakness of concrete
Excessive laitance
Segregation
All the above
Water required per bag of cement, is
7 kg
14 kg
21 kg
35 kg
For walls, columns and vertical faces of all structural members, the form work is generally removed after
24 to 48 hours
3 days
7 days
14 days
Slump test of concrete is a measure of its
Consistency
Compressive strength
Tensile strength
Impact value
How long will it take for the concrete to achieve 100% of its strength?
7 days
14 days
21 days
28 days
Under normal conditions using an ordinary cement, the period of removal of the form work, is:
7 days for beam soffits
14 days for bottom slabs of spans 4.6 m and more
21 days for bottom beams over 6 m spans
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
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 the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed
10 cm
15 cm
20 cm
25 cm
Curing
Reduces the shrinkage of concrete
Preserves the properties of concrete
Prevents the loss of water by evaporation
All of the above
Permissible compressive strength of M 300 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
300 kg/cm2
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
Ordinary concrete is not used for concrete grade
M 100
M 150
M 250
M 400
If the average compressive strength is 4000 kg/cm2 and standard deviation is 500, the co-efficient of variation is
10 %
12.5 %
15 %
18.5 %