Log Angles machine is used to test the aggregate for
Crushing strength
Impact value
Abrasion resistance
Water absorption
Correct Answer :
C. Abrasion resistance
Related Questions
For a good concrete
Aggregates should be hard and durable
Water should be free from organic materials
Cement should be sufficient to produce the required strength
All the above
Concrete is unsuitable for compaction by a vibrator if it is
Dry
Earth moist
Semi-plastic
Plastic
For an ordinary Portland cement
Residual does not exceed 10% when sieved through IS Sieve No. 9
Soundness varies from 5 to 10 mm
Initial setting time is not less than 30 minutes
Compressive stress after 7 days, is not less than 175 kg/cm2
The main reinforcement in the toe of a T-shaped R C. retaining wall is provided on
(i) Top face parallel to the wall
(ii) Top face perpendicular to the wall
(iii) Bottom face parallel to the wall
(iv) Bottom face perpendicular to the wall The correct answer is
Only (ii) is correct
(i) and (ii) are correct
(iii) and (iv) are correct
Only (iv) is correct
According to Water-Cement Ratio Law, the strength of workable plastic concrete
Depends upon the amount of water used in the mix
Does not depend upon the quality of cement mixed with aggregates
Does not depend upon the quantity of cement mixed with aggregates
All the above
Addition of pozzolana to cement
Decreases workability
Increases strength
Increases heat of hydration
None of these
Particles of 0.002 mm size are that of
Clay
Sand
Gravel
None of these
As compared to ordinary Portland cement, use of pozzolana cement
Reduces workability
Increases bleeding
Increases shrinkage
Increases strength
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
Half of the main steel in a simply supported slab is bent up near the support at a distance of x from the center of slab bearing where x is equal to (Where l is the span)
l/3
l/5
l/7
l/10
Admixtures which cause early setting and hardening of concrete are called
Workability admixtures
Accelerators
Retarders
Air entraining agents
The commercial name of white and coloured cement in India, is
Colorcrete
Silvicrete
Snowcem
All the above
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
The size of fine aggregates does not exceed
2.75 mm
3.00 mm
3.75 mm
4.75 mm
In the method of voids for determination of the quantity of cement paste, it is assumed that
Voids in coarse aggregates are filled by fine aggregates
Voids in fine aggregates are filled by the cement paste
Volume of fine aggregates is equal to total voids in coarse aggregates plus 10% extra
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
Slump test is done for
Clay
Sand
Lime
Concrete
Pozzolana cement is used with confidence for construction of
Dams
Massive foundations
R.C.C. structures
All the above
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 minimum cover in a slab should neither be less than the diameter of bar nor less than
10 mm
15 mm
25 mm
13 mm
Di-calcium silicate (C2S)
Hydrates rapidly
Generates less heat of hydration
Hardens rapidly
Provides less ultimate strength to cement
You are asked to construct a massive dam, the type of cement you will use, is
Ordinary Portland cement
Rapid hardening cement
Low heat cement
Blast furnace slag cement
If X, Y and Z are the fineness modulli of coarse, fine and combined aggregates, the percentage (P) of fine aggregates to combined aggregates, is
P = [(Z - X)/(Z - Y)] × 100
P = [(X - Z)/(Z - Y)] × 100
P = [(X - Z)/(Z + Y)] × 100
P = [(Z + X)/(Z - Y)] × 100
According to the recommendations of IS : 456-1978, the expansion joints
Are provided where plane changes abruptly
Are provided to ensure minimum resistance
Do not carry reinforcement across them
All the above
The impurity of mixing water which affects the setting time and strength of concrete, is
Sodium sulphates
Sodium chlorides
Sodium carbonates and bicarbonates
Calcium bicarbonates
The operation of removing humps and hollows of uniform concrete surface, is known as
Floating
Screeding
Trowelling
Finishing
The final operation of finishing floors, is known as
Screeding
Floating
Trowelling
Finishing
The bulk density of aggregates, depends upon
Shape
Grading
Compaction
All the above
While compacting the concrete by a mechanical vibrator, the slump should not exceed
2.5 cm
5.0 cm
7.5 cm
10 cm
Hardening of cement occurs at
Rapid rate during the first few days and afterwards it continues to increase at a decreased rate
Slow rate during the first few days and afterwards it continues to increase at a rapid rate
Uniform rate throughout its age
None of these