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All questions of Construction Materials for Civil Engineering (CE) Exam
Which IS code is used for classification of timber for seasoning purposes?- a)IS: 4970-1973
- b)IS: 1708-1969
- c)IS: 1141-1958
- d)IS: 399-1963
Correct answer is option 'C'. Can you explain this answer?
Which IS code is used for classification of timber for seasoning purposes?
a)
IS: 4970-1973
b)
IS: 1708-1969
c)
IS: 1141-1958
d)
IS: 399-1963
|
Prerna Kaur answered |
IS: 1141-1958- Classification of timber for seasoning purposes
IS: 399-1963- Classification of commercial timbers and their zonal distribution
IS: 1708-1969-Methods of testing of small specimen of timber
IS: 4970-1973-Key for Identification of commercial timbers
The maximum surface drying time (min) for class A type plastic emulsion paint as per the Indian standard is- a)45
- b)75
- c)60
- d)240
Correct answer is option 'A'. Can you explain this answer?
The maximum surface drying time (min) for class A type plastic emulsion paint as per the Indian standard is
a)
45
b)
75
c)
60
d)
240
|
Shalini Deshpande answered |
As per IS 15489 : 2004:
1. Maximum Surface drying time for class A and Class B type plastic emulsion paint is 45 minutes.
2. Maximum Surface drying time for class C and Class D type plastic emulsion paint is 90 minutes.
3. Maximum Hard drying time for class A and class B type plastic emulsion paint is 240 minutes.
4. Maximum Hard drying time for class C and class D type plastic emulsion paint is 480 minutes.
Which of the following cements contains maximum percentage of dicalcium silicate?- a)ordinary Portland cement
- b)low heat cement
- c)rapid hardening cement
- d)sulphate resisting cement
Correct answer is option 'B'. Can you explain this answer?
Which of the following cements contains maximum percentage of dicalcium silicate?
a)
ordinary Portland cement
b)
low heat cement
c)
rapid hardening cement
d)
sulphate resisting cement
|
|
Gitanjali Menon answered |
Low heat cement: This cement is manufactured by reducing the proportion of C3A and C3S and increasing the proportion of C2S. This cement shows low rate of development of strength. It contains 46% of dicalcium silicate.
Note: Whereas in Rapid hardening cement (which is formed by increasing the percentage of C3S and decreasing the percentage of C2S) contains only (9-10)% of C2S. For OPC C2S is generally 15%.
The thickness of lamin boards vary from- a)5 to 12 mm
- b)12 to 15 mm
- c)12 to 25 mm
- d)25 to 30 mm
Correct answer is option 'C'. Can you explain this answer?
The thickness of lamin boards vary from
a)
5 to 12 mm
b)
12 to 15 mm
c)
12 to 25 mm
d)
25 to 30 mm
|
|
Debolina Chavan answered |
A lamin board is a board having a core of strips, each not exceeding 7 mm in thickness, glued together face to face to form a slab which in turn glued between two or more veneers, with the direction of the grain of the core strips running at right angles to that of the adjacent outer veneers. The lamin boards are light strong and do not split or crack easily. These are used for walls, ceilings, partitions. Their thickness varies from 12 to 25 mm.
Barium Sulphate and calcium carbonate in paints are:- a)Adulterants
- b)Driers
- c)Bases
- d)Thinners
Correct answer is option 'A'. Can you explain this answer?
Barium Sulphate and calcium carbonate in paints are:
a)
Adulterants
b)
Driers
c)
Bases
d)
Thinners
|
Aarav Sharma answered |
- Adulterants: Basin sulphate, calcium carbonate, Magnesium silicate etc
- Thinners: Petroleum, Spirit, naptha, turpentine oil
- Driers: letharge, Red lead, Cobalt, zinc
- Bases: White lead, Red lead, aluminium powder.
In which classification the fat lime falls?- a)Class A
- b)Class B
- c)Class C
- d)Class D
Correct answer is option 'C'. Can you explain this answer?
In which classification the fat lime falls?
a)
Class A
b)
Class B
c)
Class C
d)
Class D
|
|
Ameya Sen answered |
Classification of Lime as a Building Material for use in Construction as per IS 712-1973 is as Follows:
1. The Class A lime are the hydraulic lime, that undergoes setting under the action of water. These are used for the construction of structures like arches and domes.
2. Class B is semi-hydraulic in nature. They are limited to small area work, like in masonry constructions.
3. Class C are called as fat lime. Another name for the same is quick lime or white lime or non-hydraulic lime. These are used for works like whitewashing, as a final coat for plastering etc. It is also used in the making of masonry mortar with the help of an additional pozzolanic material.
4. Class D is categorized for lime that is of magnesia or dolomite origin. For finishing works of plastering and white washing, the class D lime can be used
5. Kankar lime is the lime that is categorized under the class E. This lime is produced by the burning of lime nodules that are mainly found in the black soils, that constitutes silica. This forms to be hydraulic in nature. The main application of Kankar lime is in masonry mortar.
6. The siliceous dolomite lime is grouped under the class F lime. This is mainly used in the finishing coat of plaster or for its undercoat.
Toughness index of good building stone should not be less than:- a)10
- b)13
- c)16
- d)20
Correct answer is option 'B'. Can you explain this answer?
Toughness index of good building stone should not be less than:
a)
10
b)
13
c)
16
d)
20
|
|
Pallabi Bajaj answered |
Toughness Index of Building Stone
The toughness index of a building stone is an important factor to consider when selecting materials for construction purposes. It determines the stone's ability to withstand impact and resist fragmentation. A higher toughness index indicates a stronger and more durable stone, which is desirable for building structures that need to withstand various forces and environmental conditions.
Definition of Toughness Index
The toughness index of a building stone is a measure of its resistance to impact. It is determined by conducting a toughness test, where a sample stone is subjected to repeated blows from a standard hammer until it breaks. The number of blows required to cause failure is recorded, and the average is calculated. The toughness index is then calculated as the reciprocal of the average number of blows.
Significance of Toughness Index
The toughness index is an important property to consider because it indicates the stone's ability to withstand impact loads and resist fragmentation. A stone with a higher toughness index will be more resistant to cracking, breaking, and chipping, making it suitable for use in areas where heavy loads or impacts are expected, such as building foundations or pavements.
Minimum Toughness Index
According to industry standards and best practices, the minimum toughness index of a good building stone should not be less than 13. This value ensures that the stone is strong enough to withstand typical impact loads and resist fragmentation. Stones with a toughness index below this value may be more susceptible to damage and may not provide adequate structural strength.
Selection Criteria for Building Stone
When selecting a building stone, it is essential to consider various factors, including the toughness index. Other important considerations include compressive strength, porosity, weathering resistance, and aesthetic appeal. These properties collectively determine the stone's durability, structural integrity, and suitability for specific construction applications.
Conclusion
The toughness index of a building stone is a crucial factor to consider when selecting materials for construction purposes. A higher toughness index indicates a stronger and more durable stone, which is desirable for building structures that need to withstand impact loads and resist fragmentation. The minimum toughness index for a good building stone is 13, ensuring adequate strength and durability.
The toughness index of a building stone is an important factor to consider when selecting materials for construction purposes. It determines the stone's ability to withstand impact and resist fragmentation. A higher toughness index indicates a stronger and more durable stone, which is desirable for building structures that need to withstand various forces and environmental conditions.
Definition of Toughness Index
The toughness index of a building stone is a measure of its resistance to impact. It is determined by conducting a toughness test, where a sample stone is subjected to repeated blows from a standard hammer until it breaks. The number of blows required to cause failure is recorded, and the average is calculated. The toughness index is then calculated as the reciprocal of the average number of blows.
Significance of Toughness Index
The toughness index is an important property to consider because it indicates the stone's ability to withstand impact loads and resist fragmentation. A stone with a higher toughness index will be more resistant to cracking, breaking, and chipping, making it suitable for use in areas where heavy loads or impacts are expected, such as building foundations or pavements.
Minimum Toughness Index
According to industry standards and best practices, the minimum toughness index of a good building stone should not be less than 13. This value ensures that the stone is strong enough to withstand typical impact loads and resist fragmentation. Stones with a toughness index below this value may be more susceptible to damage and may not provide adequate structural strength.
Selection Criteria for Building Stone
When selecting a building stone, it is essential to consider various factors, including the toughness index. Other important considerations include compressive strength, porosity, weathering resistance, and aesthetic appeal. These properties collectively determine the stone's durability, structural integrity, and suitability for specific construction applications.
Conclusion
The toughness index of a building stone is a crucial factor to consider when selecting materials for construction purposes. A higher toughness index indicates a stronger and more durable stone, which is desirable for building structures that need to withstand impact loads and resist fragmentation. The minimum toughness index for a good building stone is 13, ensuring adequate strength and durability.
Which one of the following is an ODD one as regards “requirements of good brick-earth”?- a)It must be free from lumps of lime.
- b)It should not be mixed with salty water.
- c)It must be non-homogeneous
- d)It should not contain vegetable and organic matter
Correct answer is option 'C'. Can you explain this answer?
Which one of the following is an ODD one as regards “requirements of good brick-earth”?
a)
It must be free from lumps of lime.
b)
It should not be mixed with salty water.
c)
It must be non-homogeneous
d)
It should not contain vegetable and organic matter
|
Anshul Chakraborty answered |
Requirements of Good Brick-earth are:
1) It must have proper proportions of sand, silt and clay.
2) It must be homogeneous
3) It should have sufficient plasticity (so that the bricks can be properly and conveniently moulded with sharp and well defined edges)
4) It must be free from lumps of lime or nodules of kankar.
5) It must be free from earth containing alkaline salts, kankar etc.
6) It must be free from pebbles, grits and lumps of earth.
7) It must not contain vegetable and organic matter.
8) It should not be mixed with salty water.
9) It should be well brunt.
Match List – I (Property of cement) with List – II (Testing apparatus) and select the correct answer using the codes given below the lists: List – I List – II(Property of cement) (Testing Apparatus )a) Specific gravity 1. Blaine’s apparatusb) Setting time 2. Le – Chatelier’s flaskc) Soundness 3. Compressometerd) Fineness 4. Autoclave 5. Vicat’s apparatus- a)A-3, B-5, C-1, D-2
- b)A-2, B-5, C-1, D-4
- c)A-2, B-5, C-4, D-1
- d)A-5, B-3, C-4, D-1
Correct answer is option 'C'. Can you explain this answer?
Match List – I (Property of cement) with List – II (Testing apparatus) and select the correct answer using the codes given below the lists:
List – I List – II
(Property of cement) (Testing Apparatus )
a) Specific gravity 1. Blaine’s apparatus
b) Setting time 2. Le – Chatelier’s flask
c) Soundness 3. Compressometer
d) Fineness 4. Autoclave
5. Vicat’s apparatus
a)
A-3, B-5, C-1, D-2
b)
A-2, B-5, C-1, D-4
c)
A-2, B-5, C-4, D-1
d)
A-5, B-3, C-4, D-1
|
|
Lekshmi Rane answered |
Le-Chatelier's Flask = For Specific Gravity
Le-Chatelier's Apparatus = Soundness due to unburnt lime
Autoclave test= Soundness due to unburnt lime and magnesia
The base material for distemper is:- a)Chalk
- b)Lime
- c)Clay
- d)Lime putty
Correct answer is option 'A'. Can you explain this answer?
The base material for distemper is:
a)
Chalk
b)
Lime
c)
Clay
d)
Lime putty
|
|
Rounak Banerjee answered |
The surface on which distemper is to be done is first cleaned with sand paper and made smooth as far as possible. After the plaster gets dried up on the wall for minimum 60 days, only then distemper is to be done. First coat of lime is done on the plastered surface and after that 2 coats of distemper is applied.
These are water paints made with base as white chalk and thinner as water and are available as dry distemper and oil bound distemper.
For a 1500 m3 of brickwork, the number of nominal brick required are:- a)97460
- b)974660
- c)75000
- d)750000
Correct answer is option 'D'. Can you explain this answer?
For a 1500 m3 of brickwork, the number of nominal brick required are:
a)
97460
b)
974660
c)
75000
d)
750000
|
|
Arshiya Roy answered |
Nominal size of brick = 20 cm × 10 cm × 10 cm
Volume of 1 Brick = (0.20*0.10*0.10) m3
Number of Bricks required in 1500m3 of brickwork is = 
Heart rot is a defect in timber which is formed:- a)By action of certain type of fungi.
- b)When there is no free circulation of air.
- c)When a branch has come out of a tree.
- d)When fungi cause chemical decomposition of wood.
Correct answer is option 'A'. Can you explain this answer?
Heart rot is a defect in timber which is formed:
a)
By action of certain type of fungi.
b)
When there is no free circulation of air.
c)
When a branch has come out of a tree.
d)
When fungi cause chemical decomposition of wood.
|
Rajeev Menon answered |
There are various types of defects in timber as a construction material. These defects in timber can be due to natural forces, fungi, insects and during seasoning and conversion. Types of these defects in timber is discussed in detail.Heart Rot in Timber. Heart rot is caused in the trees when the heart wood is attacked by fungi through its newly formed branch. This type of fungi makes the tree hollow by consuming heart wood. This defect is known as heart rot
What is the maximum allowable water absorption (%) of Indian burnt brick of class 20?- a)15
- b)5
- c)20
- d)10
Correct answer is option 'A'. Can you explain this answer?
What is the maximum allowable water absorption (%) of Indian burnt brick of class 20?
a)
15
b)
5
c)
20
d)
10
|
|
Gitanjali Menon answered |
As per IS 1077: 1992, clause 7.2, Bricks after immersion in cold water for 24 hours, water absorption shall not be more than 20 percent by weight upto class 12.5 and for the classes above 12.5 water absorption shall be between 12.5 and 15 percent.
Note: Water absorption for First class brick should not exceed 12-15 % of its dry weight. For second class brick it should be between 16-20%.
The ratio of effective height to thickness of masonry walls should not be more than:- a)50
- b)40
- c)30
- d)20
Correct answer is option 'C'. Can you explain this answer?
The ratio of effective height to thickness of masonry walls should not be more than:
a)
50
b)
40
c)
30
d)
20
|
|
Akanksha Mehta answered |
Slenderness ratio of the wall is defined as the ratio of its effective length or effective height (minimum of these two) to the effective thickness.
As per IS 456:2000, section 32.2.3,
The ratio of effective height to thickness. Hwe/t (slenderness ratio) of masonry wall shall not exceed 30.
The peculiar curved swellings found on the body of a tree, are called:- a)knots
- b)Heart rots
- c)Rind galls
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
The peculiar curved swellings found on the body of a tree, are called:
a)
knots
b)
Heart rots
c)
Rind galls
d)
None of these
|
Partho Jain answered |
Rind galls: Rind galls are curved swellings of trees which are formed at a point where a branch of the tress is improperly removed or fell down.
Heart rots: Heart rot is caused in the trees when the heart wood is attacked by fungi through its newly formed branch. This type of fungi makes the tree hollow by consuming heart wood. This defect is known as heart rot.
Knots: When the base of branches forms a mark on the stem which results dark coloured stains on the surface after conversion. This dark coloured at the central part or stem are known as Knots.
Which of the following is extensively used for construction of railway carriages?- a)Batten board
- b)Block board
- c)Fibre board
- d)Hard board
Correct answer is option 'B'. Can you explain this answer?
Which of the following is extensively used for construction of railway carriages?
a)
Batten board
b)
Block board
c)
Fibre board
d)
Hard board
|
|
Ishani Basu answered |
Block board: Block board consists of smaller timber block up to 25 mm in width. These blocks are cemented edge to edge and on each face plies up to 3 mm thickness are glued. Block board is extensively used for construction of railway carriages, bus bodies, marine and river crafts and for furniture making, partitions, panelling, prefabricated houses, etc.
Batten board: The batten board is a board having a core made up of strips of wood usually 80 mm wide, each laid separately or glued or otherwise joined to form a slat which is glued between two or more outer veneers with the direction of the grain of the core running at right angles to that of the adjacent outer veneers. These are used for door panels, table tops etc.
Note: Fibre board are used for internal finish, wall panelling, floor, flush doors, table tops. These are used for fire and sound insulation in large commercial buildings and cinema houses. Hard board imparts internal appearance and finish to the structure.
The limiting value of water absorption (%) for a class 25 Brick as specified in the Indian Standard (IS 3495) is:
- a)10
- b)20
- c)15
- d)25
Correct answer is option 'C'. Can you explain this answer?
The limiting value of water absorption (%) for a class 25 Brick as specified in the Indian Standard (IS 3495) is:
a)
10
b)
20
c)
15
d)
25
|
|
Deepika Saha answered |
The bricks, when tested in accordance with the procedure laid in IS 3495 ( Part 2) : 1992 after immersion in cold water for 24 hours, water absorption shall not be more than 20 percent by weight up to class 12'5 and 15 percent by weight for higher classes.
Shear strength of timber depends on which one of the following:- a)Lignin with fibres
- b)Medullary rays
- c)Heart wood
- d)Sapwood
Correct answer is option 'A'. Can you explain this answer?
Shear strength of timber depends on which one of the following:
a)
Lignin with fibres
b)
Medullary rays
c)
Heart wood
d)
Sapwood
|
|
Tanishq Nair answered |
Lignin is regarded as lying outside of the microfibril forming a protective sheath.
As lignin is located only on the exterior it must be responsible for cementing together the fibrils and in imparting shear resistance in the transference of stress throughout the composite.
If aggregate size of 40-50 mm is to be tested for determining the proportion of elongated aggregates, the slot length of the gauge should be:- a)45 mm
- b)53 mm
- c)90 mm
- d)81 mm
Correct answer is option 'D'. Can you explain this answer?
If aggregate size of 40-50 mm is to be tested for determining the proportion of elongated aggregates, the slot length of the gauge should be:
a)
45 mm
b)
53 mm
c)
90 mm
d)
81 mm
|
|
Sahana Dey answered |
Taking the average of size of aggregates between 40 to 50 mm.
Average size of aggregate 
m
mAn aggregate is said to be elongated if its greatest dimension is greater than 1.8 times the mean diameter.
Slot length to test elongation of aggregate = 1.8 x 45 = 81 mm.
The temperature at which the bricks are burnt in kiln varies from:- a)500° to 800° C
- b)800° to 1000°C
- c)1000° to 1200°C
- d)1200° to 1500°C
Correct answer is option 'C'. Can you explain this answer?
The temperature at which the bricks are burnt in kiln varies from:
a)
500° to 800° C
b)
800° to 1000°C
c)
1000° to 1200°C
d)
1200° to 1500°C
|
|
Anuj Chakraborty answered |
Temperature for brick burning varies from 1000° to 1200°C,
Temperature for cement burning varies from 1300° to 1500°C.
In a lime-cement plaster, ratio 1 : 1 : 6 corresponds to:
- a)Lime : cement : sand
- b)Cement : Lime : sand
- c)Lime : sand : gravel
- d)Cement : sand : gravel
Correct answer is option 'B'. Can you explain this answer?
In a lime-cement plaster, ratio 1 : 1 : 6 corresponds to:
a)
Lime : cement : sand
b)
Cement : Lime : sand
c)
Lime : sand : gravel
d)
Cement : sand : gravel
|
|
Raghav Mukherjee answered |
In lime-cement Plaster, ratio 1 : 1 : 6 corresponds to cement : lime : sand.
The type of mortar which is used for the construction works carried out in water-logged area is ________.- a)cement mortar
- b)loose mortar
- c)mortar of very low consistency
- d)mortar having high w/c ratio
Correct answer is option 'A'. Can you explain this answer?
The type of mortar which is used for the construction works carried out in water-logged area is ________.
a)
cement mortar
b)
loose mortar
c)
mortar of very low consistency
d)
mortar having high w/c ratio
|
Abhay Banerjee answered |
Depending upon the nature of civil Engineering works suitable of master should be selected or recommended. For Example – The cement mortar is used where a mortar of high strength and water resisting properties is required such as underground structures, water saturated soils, etc.
Loose mortar is used where brick work is done on less importance work
Mortar having high w/c ratio possess low strength, that’s why it is not used in waterlogged areas.
Spirit varnish generally consists of:- a)oil, wax and resin
- b)alcohol, wax and turpentine
- c)pigment and synthetic resin
- d)spirit and shellac
Correct answer is option 'D'. Can you explain this answer?
Spirit varnish generally consists of:
a)
oil, wax and resin
b)
alcohol, wax and turpentine
c)
pigment and synthetic resin
d)
spirit and shellac
|
|
Anuj Chakraborty answered |
Most resin or "gum" varnishes consist of a natural, plant- or insect-derived substance dissolved in a solvent, called spirit varnish. The solvent may be alcohol, turpentine, or petroleum-based. Some resins are soluble in both alcohol and turpentine. Generally, petroleum solvents, i.e. mineral spirits or paint thinner, can substitute for turpentine.
The resins include amber, dammar, copal, rosin, sandarac, elemi, benzoin, mastic, balsam, shellac, and a multitude of lacquers
Note: There is no wax in Spirit varnish
Which of the following class of Brick is represented as Ground moulded and is commonly used at places where brickwork is to be provided with a coat of plaster?- a)Ist Class Brick
- b)IInd Class Brick
- c)IIIrd Class Brick
- d)IVth Class Brick
Correct answer is option 'B'. Can you explain this answer?
Which of the following class of Brick is represented as Ground moulded and is commonly used at places where brickwork is to be provided with a coat of plaster?
a)
Ist Class Brick
b)
IInd Class Brick
c)
IIIrd Class Brick
d)
IVth Class Brick
|
|
Partho Choudhary answered |
IInd Class Brick: It is Ground moulded, burnt in kilns. These class of bricks have surface hair cracks. Their edges may be sharp and uniform. These are commonly used at places where brickwork is to provided with a coat of plaster.
Note: While Ist class of brick is Table moulded and IIIrd class of brick is Ground moulded but is used for unimportant works, temporary structures.
Match List I with List II and select the correct answer in respect of brick earth by using the options given below the list:List IA. SilicaB. AluminaC. LimeD. Oxide of ironList II1. Provides plasticity2. Provides bondage to clay particles3. Provides hardness4. Prevents shrinkage- a)A-4, B-3, C-2, D-1
- b)A-1, B-3, C-4, D-2
- c)A-2, B-3, C-1, D-4
- d)A-4, B-1, C-2, D-3
Correct answer is option 'D'. Can you explain this answer?
Match List I with List II and select the correct answer in respect of brick earth by using the options given below the list:
List I
A. Silica
B. Alumina
C. Lime
D. Oxide of iron
List II
1. Provides plasticity
2. Provides bondage to clay particles
3. Provides hardness
4. Prevents shrinkage
a)
A-4, B-3, C-2, D-1
b)
A-1, B-3, C-4, D-2
c)
A-2, B-3, C-1, D-4
d)
A-4, B-1, C-2, D-3
|
|
Samarth Ghoshal answered |
Functions of Various Ingredients:
Silica: It enables the brick to retain its shape, imparts durability, and prevents shrinkage and warping. Excess of silica makes the brick brittle and weak on burning. A large percentage of sand or uncombined silica in clay is undesirable. However, it is added to decrease shrinkage in burning and to increase the refractoriness of low alumina clays.
Alumina: Absorbs water and renders the clay plastic. If alumina is present in excess of the specified quantity, it produces cracks in brick on drying. Clays having exceedingly high alumina content are likely to be very refractory.
Lime: Normally constitutes less than 10 per cent of clay. Lime in brick clay has the following effects:
1. Reduces the shrinkage on drying.
2. Causes silica in clay to melt on burning and thus helps to bind it.
3. In carbonated form, lime lowers the fusion point.
4. Excess of lime causes the brick to melt and the brick looses its shape.
5. Red bricks are obtained on burning the sun dried bricks at considerably high temperature (more than 800°C). Buff-burning of bricks results due to high lime content.
Magnesia: rarely exceeding 1 per cent, affects the colour and makes the brick yellow. In burning, it causes the clay to soften at slower rate than does lime and reduces warping.
Iron: Iron oxide constituting less than 7 per cent of clay imparts the following properties:
1. Gives red colour on burning when excess of oxygen is available and dark brown or even black colour when oxygen available is insufficient. However, excess of ferric oxide makes the brick dark blue.
2. Improves impermeability and durability.
3. Tends to lower the fusion point of the clay, especially if present as ferrous oxide.
4. Gives strength and hardness.
For the construction of cement concrete floor, the maximum permissible size of aggregates is- a)4 mm
- b)6 mm
- c)8 mm
- d)10 mm
Correct answer is option 'D'. Can you explain this answer?
For the construction of cement concrete floor, the maximum permissible size of aggregates is
a)
4 mm
b)
6 mm
c)
8 mm
d)
10 mm
|
|
Ishani Basu answered |
The maximum permissible size of aggregate to be used in different construction work is as follows:
1. 40 mm for massive works like dams, retaining walls, etc.
2. 20 mm for Reinforced member.
3. 10 mm for floor.
If in a concrete mix, the fineness modulus of coarse aggregate is 6.2, the fineness modulus of fine aggregate is 2.0, and the economical value of the fineness modulus of combined aggregate is 5.2 then the proportion of the fine aggregate is- a)25%
- b)28.25%
- c)31.25%
- d)33.33%
Correct answer is option 'C'. Can you explain this answer?
If in a concrete mix, the fineness modulus of coarse aggregate is 6.2, the fineness modulus of fine aggregate is 2.0, and the economical value of the fineness modulus of combined aggregate is 5.2 then the proportion of the fine aggregate is
a)
25%
b)
28.25%
c)
31.25%
d)
33.33%
|
|
Pallabi Tiwari answered |
The proportion of fine aggregate in a concrete mix can be determined using the fineness modulus of the coarse and fine aggregates.
The fineness modulus (FM) is a measure of the fineness or coarseness of an aggregate. It is calculated by adding the cumulative percentage of aggregate retained on each of the standard sieves (i.e., 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron, and 75 micron) and dividing by 100.
Given:
Fineness modulus of coarse aggregate (FMc) = 6.2
Fineness modulus of fine aggregate (FMf) = 2.0
Economical value of the fineness modulus of combined aggregate (FMe) = 5.2
To find the proportion of fine aggregate in the mix, we can use the formula:
Proportion of fine aggregate = (FMe - FMc) / (FMf - FMc) * 100
Substituting the given values into the formula:
Proportion of fine aggregate = (5.2 - 6.2) / (2.0 - 6.2) * 100
= (-1) / (-4.2) * 100
= 0.2381 * 100
= 23.81%
Therefore, the proportion of fine aggregate in the mix is 23.81%.
However, the options provided in the question are in percentage form, so we need to convert our answer to percentage. To do this, we divide the proportion by 100:
Proportion of fine aggregate = 23.81% / 100
= 0.2381
Now, we need to find the option that is closest to the calculated proportion.
Options:
a) 25%
b) 28.25%
c) 31.25%
d) 33.33%
By comparing the calculated proportion (0.2381) with the options, we can see that option c) 31.25% is the closest value. Therefore, the correct answer is option c).
The fineness modulus (FM) is a measure of the fineness or coarseness of an aggregate. It is calculated by adding the cumulative percentage of aggregate retained on each of the standard sieves (i.e., 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron, and 75 micron) and dividing by 100.
Given:
Fineness modulus of coarse aggregate (FMc) = 6.2
Fineness modulus of fine aggregate (FMf) = 2.0
Economical value of the fineness modulus of combined aggregate (FMe) = 5.2
To find the proportion of fine aggregate in the mix, we can use the formula:
Proportion of fine aggregate = (FMe - FMc) / (FMf - FMc) * 100
Substituting the given values into the formula:
Proportion of fine aggregate = (5.2 - 6.2) / (2.0 - 6.2) * 100
= (-1) / (-4.2) * 100
= 0.2381 * 100
= 23.81%
Therefore, the proportion of fine aggregate in the mix is 23.81%.
However, the options provided in the question are in percentage form, so we need to convert our answer to percentage. To do this, we divide the proportion by 100:
Proportion of fine aggregate = 23.81% / 100
= 0.2381
Now, we need to find the option that is closest to the calculated proportion.
Options:
a) 25%
b) 28.25%
c) 31.25%
d) 33.33%
By comparing the calculated proportion (0.2381) with the options, we can see that option c) 31.25% is the closest value. Therefore, the correct answer is option c).
In a shape test of aggregate, which one the following gives the correct slot for flakiness index for a material passing 50 mm sieve and retained on 40 mm sieve?- a)25 mm
- b)27 mm
- c)81 mm
- d)30 mm
Correct answer is option 'B'. Can you explain this answer?
In a shape test of aggregate, which one the following gives the correct slot for flakiness index for a material passing 50 mm sieve and retained on 40 mm sieve?
a)
25 mm
b)
27 mm
c)
81 mm
d)
30 mm
|
|
Rashi Shah answered |
Mean dimension = (40 + 50)/2 = 45 mm
Slot for flakiness index = 
What is the quantity of cement (in kg) and of dry sand (in cubic meter) respectively required for preparing 1 cubic meter of wet cement mortar of 1 : 5 proportion?- a)270 and 1.00
- b)290 and 1.05
- c)290 and 1.00
- d)310 and 1.05
Correct answer is option 'D'. Can you explain this answer?
What is the quantity of cement (in kg) and of dry sand (in cubic meter) respectively required for preparing 1 cubic meter of wet cement mortar of 1 : 5 proportion?
a)
270 and 1.00
b)
290 and 1.05
c)
290 and 1.00
d)
310 and 1.05
|
Neha Choudhury answered |
OPTION (D)
Solution:
1 m3 of wet cement mortar =1.25 m3 of dry mortar
sum of proportions =1+5 =6
Cement = 1.256=0.208m3=312.5kg
(1 m3 cement =1500 kg)
Sand = 5X1.256=1.04m3
The phenomenon of internal cracking (seperation of fibres) in timbers due to drying stresses is called as:- a)Honeycombing
- b)Internal Stressing
- c)Hearting
- d)Hardwood Formation
Correct answer is option 'A'. Can you explain this answer?
The phenomenon of internal cracking (seperation of fibres) in timbers due to drying stresses is called as:
a)
Honeycombing
b)
Internal Stressing
c)
Hearting
d)
Hardwood Formation
|
|
Dipika Nambiar answered |
Stress is developed in the heartwood during the drying process or seasoning. For these stresses, cracks are created in the form of honeycomb texture. Honey combing occur in the inner part of the timber which cannot be identified by just seeing. This is mainly due to stresses developed during drying of timber.
Among the more common varieties of timber namely sal, mango and deodar,1. Sal is strongest2. Mango is least durable3. Deodar is lightestOf the statements:- a)1 & 2 are correct
- b)1 & 3 are correct
- c)2 & 3 are correct
- d)1, 2 & 3 are correct
Correct answer is option 'D'. Can you explain this answer?
Among the more common varieties of timber namely sal, mango and deodar,
1. Sal is strongest
2. Mango is least durable
3. Deodar is lightest
Of the statements:
a)
1 & 2 are correct
b)
1 & 3 are correct
c)
2 & 3 are correct
d)
1, 2 & 3 are correct
|
|
Swati Gupta answered |
Sal: Wood is hard, close grained, heavy and durable. It is used in bridge construction, ship building, piling etc. it is not suitable for ornamental work.
Mango: Wood is of inferior quality. It is coarse and open grained. The wood is readily attacked by white ants and decays on exposure to wet atmosphere, that's why it is least durable among these three.
Deodar: It is a timber tree providing soft wood having well defined grains, It is highly durable and has distinct annual rings.
With increase in moisture content, the bulking of sand- a)Increases
- b)Decreases
- c)First increases to a certain maximum value and then decreases
- d)First decreases to a certain minimum value and then increases
Correct answer is option 'C'. Can you explain this answer?
With increase in moisture content, the bulking of sand
a)
Increases
b)
Decreases
c)
First increases to a certain maximum value and then decreases
d)
First decreases to a certain minimum value and then increases
|
|
Devansh Banerjee answered |
Explanation:
When sand particles come in contact with water, they tend to form a thin film around them. This film of water acts as a lubricant between the sand particles and reduces the friction between them. Due to the reduction in friction, the sand particles tend to move apart, resulting in an increase in volume, which is known as bulking of sand.
The bulking of sand is influenced by various factors such as particle size, shape, texture, and moisture content. Among these factors, moisture content plays a significant role in determining the extent of bulking.
Effect of moisture content on bulking of sand:
The bulking of sand increases with an increase in moisture content up to a certain maximum value and then decreases. This behavior can be explained based on the following stages:
Initial stage:
At this stage, when the sand is dry, there is no bulking as there is no lubrication between the particles.
Stage of increasing bulking:
When a small amount of water is added to the sand, the water forms a film around the particles and reduces the friction between them. This results in an increase in volume, which is known as bulking. As the moisture content increases, the bulking also increases.
Stage of maximum bulking:
At a certain moisture content, the bulking reaches a maximum value. This is because the water film around the particles has reached its maximum thickness, and any further increase in moisture content will not result in any significant increase in bulking.
Stage of decreasing bulking:
At this stage, when the moisture content is further increased, the excess water fills the voids between the sand particles and causes them to come closer. This results in a decrease in volume, which is known as contraction. Hence, the bulking decreases with an increase in moisture content beyond the maximum value.
Conclusion:
Thus, the bulking of sand first increases to a certain maximum value and then decreases with an increase in moisture content. Understanding the bulking behavior of sand is essential in various construction activities such as concrete mix design, plastering, and masonry work.
When sand particles come in contact with water, they tend to form a thin film around them. This film of water acts as a lubricant between the sand particles and reduces the friction between them. Due to the reduction in friction, the sand particles tend to move apart, resulting in an increase in volume, which is known as bulking of sand.
The bulking of sand is influenced by various factors such as particle size, shape, texture, and moisture content. Among these factors, moisture content plays a significant role in determining the extent of bulking.
Effect of moisture content on bulking of sand:
The bulking of sand increases with an increase in moisture content up to a certain maximum value and then decreases. This behavior can be explained based on the following stages:
Initial stage:
At this stage, when the sand is dry, there is no bulking as there is no lubrication between the particles.
Stage of increasing bulking:
When a small amount of water is added to the sand, the water forms a film around the particles and reduces the friction between them. This results in an increase in volume, which is known as bulking. As the moisture content increases, the bulking also increases.
Stage of maximum bulking:
At a certain moisture content, the bulking reaches a maximum value. This is because the water film around the particles has reached its maximum thickness, and any further increase in moisture content will not result in any significant increase in bulking.
Stage of decreasing bulking:
At this stage, when the moisture content is further increased, the excess water fills the voids between the sand particles and causes them to come closer. This results in a decrease in volume, which is known as contraction. Hence, the bulking decreases with an increase in moisture content beyond the maximum value.
Conclusion:
Thus, the bulking of sand first increases to a certain maximum value and then decreases with an increase in moisture content. Understanding the bulking behavior of sand is essential in various construction activities such as concrete mix design, plastering, and masonry work.
Which of the following rocks are formed under the influence of heat or pressure or both, from pre-existing rocks?- a)Igneous Rock
- b)Sedimentary Rock
- c)Metamorphic Rock
- d)All of the Above
Correct answer is option 'C'. Can you explain this answer?
Which of the following rocks are formed under the influence of heat or pressure or both, from pre-existing rocks?
a)
Igneous Rock
b)
Sedimentary Rock
c)
Metamorphic Rock
d)
All of the Above
|
Shivam Sharma answered |
Metamorphic rocks are formed from other pre-existing rocks by the action of heat and pressure. The original rock is usually igneous, but can be sedimentary, but the rock never melts, but is recrystallised into another form over long periods of time before the metamorphic rock is formed.
Which of the following has more fire resisting characteristics?- a)marble
- b)lime stone
- c)compact sand stone
- d)granite
Correct answer is option 'C'. Can you explain this answer?
Which of the following has more fire resisting characteristics?
a)
marble
b)
lime stone
c)
compact sand stone
d)
granite
|
|
Maulik Joshi answered |
Compacted stone: It is a type of rock which has the quartz or the sand bound together with the cementing minerals like mica, feldspar etc.
Compacted stone has following properties:
(a) It is a sedimentary rock
(b) Its colour depends upon that of the feldspar.
(c) It can be used as a road metal if the higher quality stones like basalt and granite is not available.
(d) It is fire resistant.
(e) Its specific gravity is 2.25
(f) Its crushing strength varies 35 to 40 MN/m2.
Among all these Compacted sandstones has more fire resisting properties.
Rapid Hardening cement should have surface area not less than (in mm2/gm × 102):- a)2250
- b)3000
- c)3250
- d)4000
Correct answer is option 'C'. Can you explain this answer?
Rapid Hardening cement should have surface area not less than (in mm2/gm × 102):
a)
2250
b)
3000
c)
3250
d)
4000
|
|
Madhurima Banerjee answered |
Surface area for following cements is given below:
The process of taking out stones of various sizes from natural rocks is known as- a)Dressing
- b)Seasoning
- c)Quarrying
- d)None of the above
Correct answer is option 'C'. Can you explain this answer?
The process of taking out stones of various sizes from natural rocks is known as
a)
Dressing
b)
Seasoning
c)
Quarrying
d)
None of the above
|
|
Lakshmi Datta answered |
Quarrying is the process of removing the rock, sand, gravel or other minerals from the ground in order to use them to produce materials for construction or other uses.
Dressing: It is the process of giving a proper size, shape and finish to the roughly broken stones as obtained from the quarry
Gypsum is added in the manufacture of Portland cement in order to- a)shorten the setting time of cement
- b)lengthen the setting time of cement
- c)decrease the burning temperature
- d)decrease the grinding time
Correct answer is option 'B'. Can you explain this answer?
Gypsum is added in the manufacture of Portland cement in order to
a)
shorten the setting time of cement
b)
lengthen the setting time of cement
c)
decrease the burning temperature
d)
decrease the grinding time
|
|
Pranab Chaudhary answered |
Gypsum is basically a Hydrated calcium sulphate (CaSo4.2H2O). It acts as a retarder in the cement and increase the setting time of cement. In places where setting time of cement required to be more, Gypsum is added in to that cement.
Important information about Gypsum: Gypsum is a mineral and is hydrated calcium sulphate in chemical form. Gypsum plays a very important role in controlling the rate of hardening of the cement. During the cement manufacturing process, upon the cooling of clinker, a small amount of gypsum is introduced during the final grinding process. Gypsum is added to control the “setting of cement”. If not added, the cement will set immediately after mixing of water leaving no time for concrete placing.
Based on the following rocks and minerals, select the correct statement.Quartz, shale, basalt, granite, marble, gypsum, mica- a)Basalt and marble are the only metamorphic rocks
- b)There is no sedimentary rock
- c)Granite is the only igneous rock
- d)Quartz and mica are minerals
Correct answer is option 'D'. Can you explain this answer?
Based on the following rocks and minerals, select the correct statement.
Quartz, shale, basalt, granite, marble, gypsum, mica
a)
Basalt and marble are the only metamorphic rocks
b)
There is no sedimentary rock
c)
Granite is the only igneous rock
d)
Quartz and mica are minerals
|
|
Dhruba Jain answered |
Out of the Given rocks and minerals
1. Quartz is mineral
2. shale is the sedimentary rock and argillaceous rock.
3. Basalt is a siliceous rock and igneous rock
4. Granite is igneous rock and unstratified rock.
5. Marble is calcareous and metamorphic rock.
6. Gypsum is a calcareous rock.
7. Mica is a mineral
The chemical reaction that occurs when cement is mixed with water is known as- a)Hydration
- b)Segregation
- c)Bleeding
- d)Slaking
Correct answer is option 'A'. Can you explain this answer?
The chemical reaction that occurs when cement is mixed with water is known as
a)
Hydration
b)
Segregation
c)
Bleeding
d)
Slaking
|
|
Devansh Banerjee answered |
1. Portland cement is a hydraulic cement, hence it derives its strength from chemical reactions between the cement and water. The process is known as hydration.It is the reaction (series of chemical reactions) of cement with water to form the binding material. In other words, in the presence of water, the silicates (C3S and C2S) and aluminates (C3A and C4AF) form products of hydration which in time produce a firm and hard mass - the hydrated cement paste.
2. Segregation is the “Separation of constituent materials in concrete.”
3. Bleeding is a form of segregation in which water present in the concrete mix is pushed upwards due to the settlement of cement and aggregate. The specific gravity of water is low, due to this water tends to move upwards. Bleeding ordinarily occurs in the wet mix of concrete.
Of the following, one which is not a type of Portland cement is- a)Water proof Portland cement
- b)Water repellent Portland cement
- c)Water absorbing Portland cement
- d)Rapid hardening Portland cement
Correct answer is option 'C'. Can you explain this answer?
Of the following, one which is not a type of Portland cement is
a)
Water proof Portland cement
b)
Water repellent Portland cement
c)
Water absorbing Portland cement
d)
Rapid hardening Portland cement
|
|
Niharika Yadav answered |
Water absorbing cement is not a type of Portland cement.
A Portland cement interground with a water-repellent material such a stearate (e.g., sodium or aluminium); reduces capillary water transmission under little or no pressure but does not completely stop water-vapour transmission.
Rapid Hardening Portland Cement (RHPC) is Portland cement that is modified (usually by further grinding) to hydrate more rapidly in the first few hours after casting.
Consider the following statements with respect to defects of timber and identify the correct one:- a)Chip mark is the defect arises due to conversion of timber.
- b)Brown rot is the defect arises due to conversion of timber.
- c)Chip mark is the defect arises due to Fungi.
- d)Bow is the type of defect arises due to Natural forces.
Correct answer is option 'A'. Can you explain this answer?
Consider the following statements with respect to defects of timber and identify the correct one:
a)
Chip mark is the defect arises due to conversion of timber.
b)
Brown rot is the defect arises due to conversion of timber.
c)
Chip mark is the defect arises due to Fungi.
d)
Bow is the type of defect arises due to Natural forces.
|
|
Anand Kumar answered |
Defect arises due to conversion of timber:
Chip mark, Torn grain, Diagonal grain and wane.
Defect arises due to Fungi:
Heart rot, Brown rot, White rot, Dry rot, Wet rot, Sap stain and Blue stain.
Defects arises due to Natural forces:
Cup shakes, Ring shakes, Heart shakes, Star shake and radial shake.
Defects arises due to Seasoning:
Bow, warp, cup and Twist.
The rocks having aluminium or clay as their major constituent, are known as:- a)Siliceous rocks
- b)Argillaceous rocks
- c)Calcarious rocks
- d)Sedimentary rocks
Correct answer is option 'B'. Can you explain this answer?
The rocks having aluminium or clay as their major constituent, are known as:
a)
Siliceous rocks
b)
Argillaceous rocks
c)
Calcarious rocks
d)
Sedimentary rocks
|
|
Partho Choudhary answered |
Argillaceous rocks: Argillaceous rocks are those sedimentary rocks which are made up of their finest clay particles. These are those rock which contain clay or aluminium as the main constituent. These rocks are made of clay, a hydrated silicate of alumina. Such rocks are formed in the sea or lakes. However, flood deposits are more common. Examples are slate, laterite, Kaoline.
Sedimentary rocks: These are the type of rocks which are formed due to gradual deposition of materials like sand, clay etc., generally by setting water. Example are limestone and sandstone.
Siliceous rocks: These are the type of rocks which contain silica as main constituent. The granite, quartzite, gneiss is example of siliceous rocks.
Calcareous rocks: The calcareous rocks are those which contain lime or calcium carbonate as the main constituent. Example are limestone and marble.
The increased rate of strength gain of rapid hardening cement is achieved by:- a)Higher content of C3S
- b)Higher content of C3A
- c)Finer grinding of cement
- d)Both (1) & (3)
Correct answer is option 'D'. Can you explain this answer?
The increased rate of strength gain of rapid hardening cement is achieved by:
a)
Higher content of C3S
b)
Higher content of C3A
c)
Finer grinding of cement
d)
Both (1) & (3)
|
Aditya Deshmukh answered |
This cement is similar to ordinary Portland cement. As the name indicates it develops strength rapidly and as such it may be more appropriate to call it as high early strength cement.Rapid hardening cement which develops higher rate of development of strength should not be confused with quick-setting cement which only sets quickly.Rapid hardening cement develops at the age of three days, the same strength as that is expected of ordinary Portland cement at seven days.The rapid rate of development of strength is attributed to the higher fineness of grinding and higher C3S and lower C2S content.The higher fineness of cement particles expose greater surface area for action of water and also higher proportion of C3S results in quicker hydratio
Rapid hardening cement can be obtained by:- a)Fine grinding of clinker
- b)Addition of gypsum
- c)Addition of calcium sulphate
- d)Higher content of lime
Correct answer is option 'A'. Can you explain this answer?
Rapid hardening cement can be obtained by:
a)
Fine grinding of clinker
b)
Addition of gypsum
c)
Addition of calcium sulphate
d)
Higher content of lime
|
|
Subhankar Khanna answered |
Rapid hardening of cement can be obtained by fine grinding of clinker, thus increases the surface area of the cement particles, which in turn increases the rate of hydration of cement that leads to decrease in setting time of cement.
While Gypsum and calcium sulphate are retarders which increases the setting time of cement.
The timber preservative “creosote” belongs to the group of:- a)Water soluble salts
- b)Organic solvent type
- c)Tar oil type
- d)Inorganic solvent type
Correct answer is option 'C'. Can you explain this answer?
The timber preservative “creosote” belongs to the group of:
a)
Water soluble salts
b)
Organic solvent type
c)
Tar oil type
d)
Inorganic solvent type
|
|
Rounak Mehta answered |
Creosote belongs to the group of tar oil type preservatives:
Creosote is a type of timber preservative that belongs to the group of tar oil type preservatives. It is derived from the distillation of coal tar and is commonly used to protect wood from decay and insect infestation.
Properties of creosote:
- Creosote is a dark brown to black liquid with a characteristic odor.
- It is a mixture of hundreds of different chemicals, including phenols and polycyclic aromatic hydrocarbons.
Application of creosote:
- Creosote is commonly used to treat wooden utility poles, railroad ties, and marine pilings.
- It is applied to the wood through pressure treatment methods to ensure deep penetration and long-lasting protection.
Benefits of creosote:
- Creosote is known for its effectiveness in preventing decay and insect damage in wood products.
- It is a long-lasting preservative that can extend the service life of treated wood.
Concerns about creosote:
- Creosote is considered a hazardous substance due to its toxicity to humans and the environment.
- Exposure to creosote can cause skin irritation, respiratory issues, and even cancer in humans.
In conclusion, creosote is a tar oil type preservative that is widely used in the timber industry for its effectiveness in protecting wood from decay and insects. However, its toxicity raises concerns about its safe handling and disposal.
Creosote is a type of timber preservative that belongs to the group of tar oil type preservatives. It is derived from the distillation of coal tar and is commonly used to protect wood from decay and insect infestation.
Properties of creosote:
- Creosote is a dark brown to black liquid with a characteristic odor.
- It is a mixture of hundreds of different chemicals, including phenols and polycyclic aromatic hydrocarbons.
Application of creosote:
- Creosote is commonly used to treat wooden utility poles, railroad ties, and marine pilings.
- It is applied to the wood through pressure treatment methods to ensure deep penetration and long-lasting protection.
Benefits of creosote:
- Creosote is known for its effectiveness in preventing decay and insect damage in wood products.
- It is a long-lasting preservative that can extend the service life of treated wood.
Concerns about creosote:
- Creosote is considered a hazardous substance due to its toxicity to humans and the environment.
- Exposure to creosote can cause skin irritation, respiratory issues, and even cancer in humans.
In conclusion, creosote is a tar oil type preservative that is widely used in the timber industry for its effectiveness in protecting wood from decay and insects. However, its toxicity raises concerns about its safe handling and disposal.
Portland cement is heavier than water by about:- a)1.15 times
- b)2.30 times
- c)3.85 times
- d)3.15 times
Correct answer is option 'D'. Can you explain this answer?
Portland cement is heavier than water by about:
a)
1.15 times
b)
2.30 times
c)
3.85 times
d)
3.15 times
|
|
Shail Rane answered |
Specific Gravity of Portland cement is 3.15 which represents its weight of about 3.15 times as that of water for the same volume.
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