For given water content, workability decreases if the concrete aggregates contain an excess of
Thin particles
Flat particles
Elongated particles
All the above
Correct Answer :
D. All the above
Related Questions
Ordinary Portland cement is manufactured from
Lime stone and clay
Gypsum and lime
Pozzolana
Lime, pozzolana and clay
If the depth of moist sand in a cylinder is 15 cm and the depth of the sand when fully inundated with water is 12 cm, the bulking of the moist sand, is
10 %
12 %
15 %
25 %
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
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
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
Select the incorrect statement
The loss of pre-stress is more in pre-tensioning system than in posttensioning system.
Pre-tensioning system has greater certainty about its durability.
For heavy loads and large spans in buildings or bridges, posttensioning system is cheaper than pre-tensioning system
None of the above
Addition of pozzolana to cement causes
Reduction in permeability
Loss of heat of hydration
Reduction in bleeding
All the above
The lower water cement ratio in concrete, introduces
Smaller creep and shrinkage
Greater density and smaller permeability
Improved frost resistance
All the above
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
A higher modular ratio shows
Higher compressive strength of concrete
Lower compressive strength of concrete
Higher tensile strength of steel
Lower tensile strength of steel
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
Permissible compressive strength of M 200 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
250 kg/cm2
Grading of sand causes great variation in
Workability of concrete
Strength of concrete
Durability of concrete
All the above
Pick up the correct statement from the following:
High percentage of C3S and low percentage of C2S cause rapid hardening
High percentage of C3S and low percentage of C2S make the cement less resistive to chemical attack
Low percentage of C3S and high percentage of C2S contribute to slow hardening
All the above
The process of proper and accurate measurement of concrete ingredients for uniformity of proportion, is known
Grading
Curing
Mixing
Batching
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
Pick up the correct statement from the following:
The free water is the amount of water added while mixing and the amount of water held on the surface of the aggregates prior to mixing
The total water is the free water and the amount actually absorbed by the aggregates
Neither (a) nor (b)
Both (a) and (b)
Slump test of concrete is a measure of its
Consistency
Compressive strength
Tensile strength
Impact value
Which of the following statements is incorrect?
Higher Vee-Bee time shows lower workability
Higher slump shows higher workability
Higher compacting factor shows higher workability
None of the above
The individual variation between test strength of sample should not be more than
± 5 % of average
± 10 % of average
± 15 % of average
± 20 % of average
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
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
To obtain a very high strength concrete, use very fine grained
Granite
Magnetite
Barite
Volcanic scoria
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
For ensuring quality of concrete, use
Single sized aggregates
Two sized aggregate
Graded aggregates
Coarse aggregates
For the construction of cement concrete dams, the maximum permissible size of the aggregates, is
40 mm
50 mm
60 mm
70 mm
In a spherical dome subjected to concentrated load at crown or uniformly distributed load, the meridional force is always
Zero
Tensile
Compressive
Tensile or compressive
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
Allowable shear strength of concrete, depends upon
Shear strength
Tensile strength
Compressive strength
None of these
Vicat apparatus is used for
Fineness test
Consistency test
Test for setting time
Test for tensile strength