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
Correct Answer :
D. All the above
Related Questions
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 maximum value of hoop compression in a dome is given by
wR / 4d
wR/2d
wR/d
2wR/d Where, w = load per unit area of surface of dome R = radius of curvature d = thickness of dome
Vicat's apparatus is used for
Fineness test
Consistency test
Setting time test
Soundness test
The size of fine aggregates does not exceed
2.75 mm
3.00 mm
3.75 mm
4.75 mm
Log Angles machine is used to test the aggregate for
Crushing strength
Impact value
Abrasion resistance
Water absorption
Addition of pozzolana to cement causes
Reduction in permeability
Loss of heat of hydration
Reduction in bleeding
All the above
Air entrainment in the concrete increases
Workability
Strength
The effects of temperature variations
The unit weight
If fineness modulus of sand is 2.5, it is graded as
Very fine sand
Fine sand
Medium sand
Coarse sand
Pick up the incorrect statement from the following:
With passage of time, the strength of cement increases
With passage of time, the strength of cement decreases
After a period of 24 months, the strength of cement reduces to 50%
The concrete made with storage deteriorated cement, gains strength with time
The minimum cover to the ties or spirals should not be less than
15 mm
20 mm
25 mm
50 mm
To obtain a very high strength concrete, use very fine grained
Granite
Magnetite
Barite
Volcanic scoria
If the slump of a concrete mix is 60 mm, its workability is
Very low
Low
Medium
High
I.S. Sieve Nos. 10 mm and 4.75 mm are generally used for grading of
Coarse aggregates
Fine aggregates
Neither (a) nor (b)
Both (a) and (b)
Vicat apparatus is used for
Fineness test
Consistency test
Test for setting time
Test for tensile strength
If 20 kg of coarse aggregate is sieved through 80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron and 150 micron standard sieves and the weights retained are 0 kg, 2 kg, 8 kg, 6 kg, 4 kg respectively, the fineness modulus of the aggregate, is
7.30
7.35
7.40
7.45
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
If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called
Balanced beam
Under-reinforced beam
Over-reinforced beam
None of the above
Pick up the incorrect statement from the following:
The degree of grinding of cement, is called fineness
The process of changing cement paste into hard mass, is known as setting of cement
The phenomenon by virtue of which cement does not allow transmission of sound, is known as soundness of cement
The heat generated during chemical reaction of cement with water, is known as heat of hydration
Bulking of sand is
Mixing of different sizes of sand particles
Mixing of lime with sand
Maximum water with sand
Swelling of sand when wetted
The recommended value of modular ratio for reinforced brick work is
18
30
40
58
In case of hand mixing of concrete, the extra cement to be added is
5 %
10 %
15 %
20 %
Assertion A : The load factor for live load is greater than that for dead load. Reason R : The live loads are more uncertain than dead loads. Select your answer based on the coding system given below:
Both A and R is true and R is the correct explanation of A
Both A and R is true but R is not the correct explanation of A
A is true but R is false
A is false but R is true
Proper batching ensures
Economy
Durability
Workability
All the above
In T-shaped R C. retaining walls, the main reinforcement in the stem is provided on
The front face in one direction
The front face in both directions
The inner face in one direction
The inner face in both directions
Setting time of cement increases by adding
Gypsum
Hydrogen peroxide
Calcium chloride
Sodium oxide
Select the correct statement
Elastic modulus of high tensile steel is nearly the same as that of mild steel
Elastic modulus of high tensile steel is more than that of mild steel
Carbon percentage in high carbon steel is less than that in mild steel
High tensile steel is cheaper than mild steel
For a reinforced concrete section, the shape of shear stress diagram is
Wholly parabolic
Wholly rectangular
Parabolic above neutral axis and rectangular below neutral axis
Rectangular above neutral axis and parabolic below neutral axis
Pick up the correct statement from the following:
Bulking of sand is caused due to formation of a thin film of surface moisture
Fine sand bulks more than coarse sand
The volume of fully saturated sand, is equal to the volume of dry and loose sand
All the above
The approximate value of the ratio between direct tensile strength and flexural strength is
0.33
0.5
0.75
1.0
Minimum grade of concrete to be used in reinforced concrete as per IS: 4561978 is
M 15
M 20
M 10
M 25