Separation of water or water sand cement from a freshly concrete, is known
Bleeding
Creeping
Segregation
Flooding
Correct Answer :
A. Bleeding
Related Questions
Pick up the correct statement from the following:
Calcium chloride acts as a retarder
Calcium chloride acts as an accelerator
Gypsum (calcium sulphate) acts as a retarder
Both (b) and (c)
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
If 1500 g of water is required to have a cement paste 1875 g of normal consistency, the percentage of water is,
20 %
25 %
30 %
35 %
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
The percentage of voids in cement is approximately
25 %
40 %
60 %
80 %
If the average compressive strength is 4000 kg/cm2 and standard deviation is 500, the co-efficient of variation is
10 %
12.5 %
15 %
18.5 %
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
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)
An ordinary Portland cement when tested for its fineness, should not leave any residue on I.S. sieve No. 9, more than
5 %
10 %
15 %
20 %
Ordinary concrete is not used for concrete grade
M 100
M 150
M 250
M 400
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
As compared to ordinary Portland cement, use of pozzolana cement
Reduces workability
Increases bleeding
Increases shrinkage
Increases strength
The strength of concrete after one year as compared to 28 days strength is about
10 to 15% more
15 to 20% more
20 to 25% more
25 to 50% more
In pre-stressed concrete
Forces of tension and compression change but lever arm remains unchanged
Forces of tension and compressions remain unchanged but lever arm changes with the moment
Both forces of tension and compression as well as lever arm change
Both forces of tension and compression as well as lever arm remain unchanged
Log Angles machine is used to test the aggregate for
Crushing strength
Impact value
Abrasion resistance
Water absorption
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
Curing
Reduces the shrinkage of concrete
Preserves the properties of concrete
Prevents the loss of water by evaporation
All of the above
The main object of compaction of concrete, is:
To eliminate air holes
To achieve maximum density
To provide intimate contact between the concrete and embedded materials
All the above
In counterfort retaining walls, the main reinforcement in the stem at support is
Not provided
Provided only on inner face
Provided only on front face
Provided both on inner and front faces
The maximum percentage of chemical ingredient of cement is that of
Magnesium oxide
Iron oxide
Silica
Lime
The most commonly used admixture which prolongs the setting and hardening time is
Gypsum
Calcium chloride
Sodium silicate
All of the above
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
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
Examine the following statements: (i) Factor of safety for steel should be based on its yield stress, (ii) Factor of safety for steel should be based on its ultimate stress, (iii) Factor of safety for concrete should be based on its yield stress, (iv) Factor of safety for concrete should be based on its ultimate stress. The correct statements are
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
The load carrying capacity of a helically reinforced column as compared to that of a tied column is about
5 % less
10 % less
5 % more
10 % more
The size of fine aggregates does not exceed
2.75 mm
3.00 mm
3.75 mm
4.75 mm
The preliminary test is repeated if the difference of compressive strength of three test specimens, exceeds
5 kg/cm2
8 kg/cm2
10 kg/cm2
15 kg/cm2
1% of voids in a concrete mix would reduce its strength by about
5 %
10 %
15 %
20 %
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
Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is
30 %
40 %
50 %
60 %