Hydration of cement is due to chemical action of water with
Tricalcium silicate and dicalcium silicate
Dicalcium silicate and tricalcium aluminate
Tricalcium aluminate and tricalcium alumino ferrite
All the above
Correct Answer :
D. All the above
Related Questions
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
M10 grade of concrete approximates
1 : 3 : 6 mix
1 : 1 : 2 mix
1 : 2 : 4 mix
1 : 1.5 : 3 mix
For ensuring quality of concrete, use
Single sized aggregates
Two sized aggregate
Graded aggregates
Coarse aggregates
The cement becomes useless if its absorbed moisture content exceeds
1 %
2 %
3 %
5 %
The compressive strength of 100 mm cube as compared to 150 mm cube is always
Less
More
Equal
None of the above
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
In a ring beam subjected to uniformly distributed load (i) Shear force at mid span is zero (ii) Shear force at mid span is maximum (iii) Torsion at mid span is zero (iv) Torsion at mid span is maximum The correct answer is
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
The effect of adding calcium chloride in concrete is (i) To increase shrinkage (ii) To decrease shrinkage (iii) To increase setting time (iv) To decrease setting time The correct answer is
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
As compared to ordinary Portland cement, use of pozzolana cement
Reduces workability
Increases bleeding
Increases shrinkage
Increases strength
The shrinkage of concrete
Is proportional to water content is the mix
Is proportional to cement concrete
Increases with age of concrete
All the above
The shuttering of a hall measuring 4 m × 5 m, can be removed after
5 days
7 days
10 days
14 days
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
Segregation is responsible for
Honey-combed concrete
Porous layers in concrete
Surface scaling in concrete
All the above
Slump test is done for
Clay
Sand
Lime
Concrete
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 correct statement from the following:
An increase in water content must be accompanied by an increase in cement content
Angular and rough aggregates reduce the workability of the concrete
The slump of the concrete mix decreases due to an increase in temperature
All the above
In a spherical dome the hoop stress due to a concentrated load at crown is
Compressive everywhere
Tensile everywhere
Partly compressive and partly tensile
Zero
Pick up the incorrect statement from the following:
Tricalcium silicate (C3S) hydrates rapidly
Tricalcium silicate (C3S) generates more heat of hydration
Tricalcium silicate (C3S) develops early strength
Tricalcium silicate (C3S) has more resistance to sulphate attack
The most commonly used admixture which prolongs the setting and hardening time is
Gypsum
Calcium chloride
Sodium silicate
All of the above
If the foundations of all the columns of a structure are designed on the total live and dead load basis, then
There will be no settlement of columns
There will be no differential settlement
The settlement of exterior columns will be more than interior columns
The settlement of interior columns will be more than exterior columns
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
Batching error means inaccuracy in the quantity of
Aggregates
Cement
Water
All the above
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
For batching 1:3:6 concrete mix by volume, the ingredients required per bag of 50 kg cement, are:
70 litres of sand and 120 litres of aggregates
70 kg of sand and 140 litres of aggregates
105 litres of sand and 140 litres of aggregates
105 litres of sand and 210 litres of aggregates
According to ISI recommendations, the maximum depth of stress block for balanced section of a beam of effective depth d is
0.43 d
0.55 d
0.68 d
0.85 d
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
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
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
For the construction of thin R.C.C. structures, the type of cement to be avoided, is
Ordinary Portland cement
Rapid hardening cement
Low heat cement
Blast furnace slag cement
The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called
Segregation
Bleeding
Bulking
Creep