Curing
Reduces the shrinkage of concrete
Preserves the properties of concrete
Prevents the loss of water by evaporation
All of the above
Correct Answer :
D. All of the above
Related Questions
Specified compressive strength of concrete is obtained from cube tests at the end of
3 days
7 days
21 days
28 days
Sands of zone I are:
Course
Medium
Medium to fine
Fine
Permissible compressive strength of M 300 concrete grade is
100 kg/cm2
150 kg/cm2
200 kg/cm2
300 kg/cm2
Workability improved by adding
Air-entraining agent
Foaming agent
Oily-agent
All the above
If the slump of a concrete mix is 60 mm, its workability is
Very low
Low
Medium
High
Pick up the incorrect statement from the following:
The bottom and top ends of slump mould are parallel to each other
The axis of the mould is perpendicular to the end faces
The internal surface of the mould is kept clean and free from set cement
The mould is in the form of a frustum of hexagonal pyramid
The factor of safety for
Steel and concrete are same
Steel is lower than that for concrete
Steel is higher than that for concrete
None of the above
Concrete is unsuitable for compaction by a vibrator if it is
Dry
Earth moist
Semi-plastic
Plastic
For the design of retaining walls, the minimum factor of safety against overturning is taken as
1.5
2.0
2.5
3.0
According to IS: 4561978, the column or the strut is the member whose effective length is greater than
The least lateral dimension
2 times the least lateral dimension
3 times the least lateral dimension
4 times the least lateral dimension
Pick up the incorrect statement from the following:
Concrete for which preliminary tests are conducted, is called controlled concrete
Bulking of sand depends upon the fineness of grains
Concrete mix 1 : 6 : 12, is used for mass concrete in piers
All the above
An excess of flaky particles in concrete aggregates
Decreases the workability
Increases the quantity of water and sand
More than 15% are not desirable
All the above
While designing the pile as a column, the end conditions are nearly
Both ends hinged
Both ends fixed
One end fixed and other end hinged
One end fixed and other end free
High carbon content in the steel causes
Decrease in tensile strength but increase in ductility
Increase in tensile strength but decrease in ductility
Decrease in both tensile strength and ductility
Increase in both tensile strength and ductility
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
High temperature
Increases the strength of concrete
Decreases the strength of concrete
Has no effect on the strength of concrete
None of these
The concrete mix which causes difficulty in obtaining a smooth finish, possess
Segregation
Internal friction
Hardness
Bleeding
Sand generally contains salt if it is obtained from:
Nala beds
River beds
Sea beds
None of these
For compacting plain concrete road surface of thickness less than 20 cm, we use
Internal vibrator
Screed vibrator
Form vibrator
None of these
The maximum thickness of concrete floor of a cement warehouse, is
10 cm
15 cm
20 cm
25 cm
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 cement becomes useless if its absorbed moisture content exceeds
1 %
2 %
3 %
5 %
The light weight aggregates are obtained from
Sedimentary rocks
Metamorphic rocks
Igneous rocks
Volcanic source
The factor which affects workability, is
Water content and its temperature
Shape and size of the aggregates
Air entraining agents
All the above
The final operation of finishing floors, is known as
Screeding
Floating
Trowelling
Finishing
The minimum percentage of chemical ingredient of cement is that of
Magnesium oxide
Iron oxide
Alumina
Lime
Pick up the incorrect statement applicable to the field test of good cement.
When one thrusts one's hand into a bag of cement, one should feel warm
The colour of the cement is bluish
By rubbing cement in between fingers, one should feed rough
All the above
C.R.R.I. charts are used to obtain a relationship between strength of concrete and
Water cement ratio
Workability
Grading of aggregate
Fineness modulus
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
For a concrete mix 1:3:6 and water cement ratio 0.6 both by weight, the quantity of water required per bag, is
10 kg
12 kg
14 kg
16 kg