The 28 days cube strength of mass concrete using aggregates of maximum size 5 cm for gravity dams should be
Between 150 to 300 kg/cm2
Between 350 to 600 kg/cm2
Between 150 to 500 kg/cm2
Below 200 kg/cm2
Correct Answer :
D. Below 200 kg/cm2
Related Questions
Pick up the incorrect statement from the following:
In properly graded aggregates, bulk density is more
In single size aggregates, bulk density is least
In single size aggregates, bulk density is maximum
None of these
If the size of panel in a flat slab is 6 m × 6 m, then as per Indian Standard Code, the widths of column strip and middle strip are
3.0 m and 1.5 m
1.5 m and 3.0 m
3.0 m and 3.0 m
1.5 m and 1.5 m
The lower water cement ratio in concrete, introduces
Smaller creep and shrinkage
Greater density and smaller permeability
Improved frost resistance
All the above
The size of fine aggregates does not exceed
2.75 mm
3.00 mm
3.75 mm
4.75 mm
The average permissible stress in bond for plain bars in tension is
Increased by 10% for bars in compression
Increased by 25% for bars in compression
Decreased by 10% for bars in compression
Decreased by 25% for bars in compression
Pick up the correct statement from the following:
Lime in excess, causes the cement to expand and disintegrate
Silica in excess, causes the cement to set slowly
Alumina in excess, reduces the strength of the cement
All the above
Strength of concrete increases with
Increase in water-cement ratio
Increase in fineness of cement
Decrease in curing time
Decrease in size of aggregate
Poisson's ratio for concrete
Remains constant
Increases with richer mixes
Decreases with richer mixes
None of the above
Water required per bag of cement, is
7 kg
14 kg
21 kg
35 kg
The minimum percentage of chemical ingredient of cement is that of
Magnesium oxide
Iron oxide
Alumina
Lime
The slab is designed as one way if the ratio of long span to short span is
Less than 1
Between 1 and 1.5
Between 1.5 and 2
Greater than 2
The fineness modulus of fine aggregate is in the range of
2.0 to 3.5
3.5 to 5.0
5.0 to 7.0
6.0 to 8.5
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 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 %
Bulking of sand is maximum if moisture content is about
2 %
4 %
6 %
10 %
Pick up the incorrect statement from the following. While performing preliminary test on concrete
Proportions of the material and water should be the same as to be used at the work site
Cement should be mixed by hand in order to maintain uniformity
Concrete mix should be stored in air-tight containers
Concrete ingredients should be kept at a temperature of 37° ± 2°C
Sinking of an intermediate support of a continuous beam (i) Reduces the negative moment at support (ii) Increases the negative moment at support (iii) Reduces the positive moment at center of span (iv) Increases the positive moment at center of span The correct answer is
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
Specified compressive strength of concrete is obtained from cube tests at the end of
3 days
7 days
21 days
28 days
The load factors for live load and dead load are taken respectively as
1.5 and 2.2
2.2 and 1.5
1.5 and 1.5
2.2 and 2.2
Pick up the correct statement from the following:
Continuous grading is not necessary for obtaining a minimum of air voids
The omission of a certain size of aggregate is shown by a straight horizontal line on the grading curve
The omission of a certain size of aggregate in concrete increases the workability but also increases the liability to segregation
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
Log Angles machine is used to test the aggregate for
Crushing strength
Impact value
Abrasion resistance
Water absorption
To obtain a very high strength concrete, use very fine grained
Granite
Magnetite
Barite
Volcanic scoria
To hydrate 500kg of cement full water needed, is
100 kg
110 kg
120 kg
130 kg
Pick up the incorrect statement from the following:
A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive quantity of water
The strength of concrete decreases as the water cement ratio increases
Good compaction by mechanical vibrations, increases the strength of concrete
None of these
If the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed
10 cm
15 cm
20 cm
25 cm
If the permissible stress in steel in tension is 140 N/mm², then the depth of neutral axis for a singly reinforced rectangular balanced section will be
0.35 d
0.40 d
0.45 d
Dependent on grade of concrete also
A concrete using an air entrained cement
Has strength less than 10% to 15%
Has more resistance to weathering
Is more plastic and workable
Is free from segregation and bleeding
Inert material of a cement concrete mix, is
Water
Cement
Aggregate
None of these
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