Internal moisture conditions on hydration continue till complete strength is gained
Concrete specimens may be tested at any temperature
Concrete specimens need be of same age
Concrete specimens need be of same size
B. Concrete specimens may be tested at any temperature
According to the petrological characteristics, concrete aggregates are classified as heavy weight, normal weight and light weight
According to the shape of the particles, concrete aggregates are classified as rounded irregular, angular and flaky
According to the surface texture of the particles, the concrete aggregates are classified as glassy, smooth, granular, rough, crystalline, honey combed and porous
All the above
Thorough mixing of concrete is required
Proper compaction of concrete is required
Proper curing of concrete is required
All the above
1/4
1/5
1/6
1/8
18
30
40
58
Equal to the mean size
Twice the mean size
Thrice the mean size
Four times the mean size
20 kN/cm²
200 kN/cm²
200 kN/mm²
2 × 106 N/cm²
1.5 and 2.2
2.2 and 1.5
1.5 and 1.5
2.2 and 2.2
To eliminate air holes
To achieve maximum density
To provide intimate contact between the concrete and embedded materials
All the above
1100° and 1200°C
1200° and 1300°C
1300° and 1400°C
1400° and 1500°C
1 : 2 : 4
1 : 3 : 6
1 : 1 ½ : 3
1 : 1 : 2
1 : 3 : 6 mix
1 : 1 : 2 mix
1 : 2 : 4 mix
1 : 1.5 : 3 mix
One cantilever
Two cantilevers
Three cantilevers
Four cantilevers
To decrease it
To increase it
Either to decrease or to increase it
To keep it unchanged
Increases the strength of concrete
Decreases the strength of concrete
Has no effect on the strength of concrete
None of these
Aggregates
Cement
Water
All the above
Reduces the strength
Increases the strength
Does not change the strength
All of the above
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
Soundness of cement
Hardness of cement
Strength of cement
Durability of cement
Sodium sulphates
Sodium chlorides
Sodium carbonates and bicarbonates
Calcium bicarbonates
(i) and (iii)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
Water cement ratio is reduced
Proportion of aggregates is reduced
An allowance for the entrained air is made
All the above
Shape
Grading
Compaction
All the above
0.15
0.12
0.30
1.00
Dams
Massive foundations
R.C.C. structures
All the above
Shear strength
Tensile strength
Compressive strength
None of these
0
10
20
30
Magnesium oxide
Iron oxide
Silica
Lime
5 % less
10 % less
5 % more
10 % more
10 mm
15 mm
25 mm
13 mm
Dry
Earth moist
Semi-plastic
Plastic