Test: Civil Engineering- 3 - SSC JE MCQ

Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. It has maximum weathering resistance characteristics among Limestone, phyllite, slate.

The burning process is carried out in the rotary kiln while the raw materials are rotated at 1-2 rpm at its longitudinal axis.

The rotary kiln is made up of steel tubes having the diameter of 2.5-3.0 meter and the length differs from 90-120 meter.

The inner side of the kiln is lined with refractory bricks.

Different methods of Timber Preservation are:

i) Brushing

ii) Spraying

iii) Injecting under pressure

iv) Dipping and stepping

v) Charring

vi) Hot and cold open tank treatment

Charring is basically a burning of timber surface (old method of preservation of timber). In this method, the timber surface is wetted for 30 minutes and burnt up to a depth of 15 mm from top surface. The burnt surface protects the inner timber from white ants, fungi, etc.

This method is not suitable for exterior wood works.

Dipping is another type of preserving the timber, In this method, timber is dipped directly in the preservative solution. Hence, the solution penetrates the timber better than the case of brushing or spraying.

In Hot and cold open tank treatment method, the timber is placed in an open tank which contains preservative solution. This solution is then heated for few hours at 85 to 95 degree Celsius. Then, the solution is allowed to cool, and timber gets submerged with this gradual cooling

Tricalcium Aluminate: C₃A is formed within 24 hours of the addition of water in the cement and is responsible for maximum evolution of heat of hydration. It is the first compound that is formed after addition of water and sets early.

Tetracalcium aluminoferrite: C₄AF is also formed within 24 hours of the addition of water in the cement but its individual contribution to the overall strength of the cement is insignificant.

Tricalcium silicate: C₃S is formed within a week or so of the addition of water in the cement and is responsible for the early development of strength of the cement.

Dicalcium silicate: C₂S is the last compound that is formed after the addition of water in the cement which may require a year or so for its formation. It is responsible for the progressive strength of the cement.

Carrier: It is an oily liquid in which the base and pigment are soluble. It facilitates the paint to be conveniently spread evenly over the surface by means of a brush. It acts as a binder for the base and cause it to stick to the surface.

Oils most commonly used as vehicles are: Linseed oil, Poppy oil. Nut oil and Tung oil.

Driers: These are metallic compounds which when added to the paint in small quantities accelerate the process of drying of the paint. Driers have a tendency to affect the colour of the paint and also to destroy the elasticity of the paint.

Litharge, manganese dioxide, lead acetate and cobalt are the usual driers, out of which litharge is most commonly used.

As per IS 3495 (part 1): 1992, Procedure for testing of the compressive strength of Burnt clay solid brick is:

1. Place the specimen with flat faces horizontal, and mortar filled face facing upwards between two three-ply plywood sheets each of 3 mm thickness and carefully centered between plates of the testing machine.

2. Apply load axially at a uniform rate of 14 N/mm* (140 kgf/cm²) per minute till failure occurs and note the maximum load at failure.

3. The load at failure shall be the maximum load at which the specimen fails to produce any further increase in the indicator reading on the testing machine.

Preconditioning before the test:

Immerse of brick in water at room temperature for 24 hours.

As per IS 287:1993:

The recommended moisture content of timber used as a structural element for windows is depend upon Zone area and thickness.

It lies between 10 to 16% for thickness of 50 mm and above

It lies between 8 to 14% for thickness less than 50 mm.

The opening left in flat roofs for lightening purposes is known as Lantern.

Dormer windows are provided for sloped roofs. They provide ventilation as well as lighting to the room. They also enhance aesthetic sense of room.

Skylights are generally provided on the top of sloped roofs. To admit light into the rooms, sky lights are provided. It is provided parallel to the sloping surface. Sky lights can be opened when we required.

As per IS 2180 : 1988:

Heavy duty burnt clay bricks shall be manufactured either by pressing or extrusion. They shall be made from a processed clay or clays blended in right proportion.

Average compressive strength of heavy-duty bricks shall not be less than 40 N/mm²

The essential tools used in the hand moulding process are:

i) a brick mould

ii) cutting wire or strike

iii) wooden plates called pallets

iv) a stock board

Frog mark of bricks are made by using a pair of pallet boards.

Clay imparts hydraulicity to the lime and makes it insoluble in water, if it is in excess it arrests slaking if it is in deficiency it retards slaking.

Presence of sulphur in small quantity reduces the slaking and accelerates the setting process of lime.

The first coat applied to the newly wall is called as “undercoat”.

In case of brick masonry, the thickness of first coat plaster is in general 12 mm and in case of concrete masonry this thickness varies from 9 to 15 mm.

Annual sinking fund (I) is given by:

Where,

S = total amount of sinking fund to be accumulated = 3500 Rs

i = rate of interest = 5% = 0.05

n = number of years required to be accumulate the sinking fund = 20 years

Quantity of brickwork = L x B x H

= 5 x 3.5 x 0.20

= 3.5 m³

Cost of 1 m³ of brickwork = Rs. 345

Cost of 3.5 m³ of brickwork = 3.5 x 345 = Rs. 1207.5

Centage charges: When the engineering department takes up the work of other department, a percentage amount of 10 to 15 % of the estimate cost is charged to meet the expenses of establishment, designing, planning, supervision etc and this percentage charge is known as Centage charge.

Technical sanction means the sanction of the detailed estimate, design calculations, quantities of work, rates and cost of the work by the competent authority of the engineering department. After the technical sanction of the estimate is given then only the work is taken up for construction.

Note: Fund allotment is a part of Expenditure sanction.

The capacity of doing work by an artesian or skilled labour in the form of quantity of work per day is known as out turn of the labour.

i) Doors and window frames or chowkhats are computed in cubic meter.

ii) Door or Window Leaves or Shutter are computed in square meter.

iii) Wood work such as wooden beams, burgahs, posts, wooden roof trusses, chowkhats etc are computed in cubic meter.

Circulation area is the floor area of verandahs, passages, corridors, balconies, entrance hall, porches, stair cases etc. which are used for movements of persons using the building.

The Circulation area shall comprise of the following items:

i) Verandahs and balconies

ii) Passages and corridors

iii) Entrance halls

iv) Stair case and mumties

v) Shafts for lifts

Items included in Tender notice are:

i) Description of work

ii) Estimated cost of work

iii) Date and Time of the tender

iv) Amount of Earnest money

v) Security money

vi) Time of completion

Skirting up to 30 cm in height shall be measured in running meter while skirting or dado exceeding 30 cm shall be measured in square meter stating the type of finish.

For 20 m chain length,

Degree of curve (D) is given by:

Note:

For 30 m chain length,

Degree of curve (D) is given by:

Let True length of the line = L

True or designated length of chain (l) = 100 links

Wrong length of line measured (L’) = 2000 links

Wrong length of the chain (l’) = 100 - 0.5 = 99.5 links

l’ × L’ = l × L

Hypotenuse allowance (C_m) for 30 m chain is given by:

Distance of visible horizon is given by:

H = height of visible horizon (meters)

D = Distance of visible horizon (km)

Refraction correction is given by:

Where,

d = distance in (meters)

R = radius of earth = 6370 km

Liquid limit, W_L = 50%

Plastic limit, W_P = 25%

Moisture content, W = 35%

Consistency index,

Void ratio in loosest state = e_max

Void ratio in dense state = e_min

Natural void ratio = e

So the ratio of the difference between the void ratio of soil in loosest state and its natural void ratio to the difference between the void ratio in loosest state and fully dense state is called Relative density.

By relative density, the field compaction is how much achieved is determined for coarse grained soil.

The relative density of compacted dense sand is experimentally observed to be 0.95.