Test: Civil Engineering- 2 - SSC JE MCQ

Fineness of cement is property of cement that indicate particle size of cement and specific surface area and indirectly effect heat of hydration. Fineness of cement affects hydration rate hence the rate of strength gain.

The smaller the particle size, the greater the surface area-to-volume ratio, and thus, the more area available for water-cement interaction per unit volume.

Therefore, finer cement reacts faster with water and the rate of development of strength and corresponding heat of hydration is high. Hence with increase in fineness of cement, rate of hydration increases but the total amount of heat generation will remain same.

Pigments are used to hide the surface imperfections and to impart the desired colour. They protect the paint film by reflecting the destructive ultraviolet light which acts as a catalytic agent for the destructive oxidation of the film.

Drier are used in paints for specific purpose e.g. as catalyst for the oxidation, polymerisation and condensation of the vehicle in paint. The quantity of drier is limited to 8%, excess of it affects the elasticity of paints leading to flaking failure.

Adulterants bring down the overall cost, reduce the weight and increase the durability. Adulterants also help to reduce cracking of dry paint and sometimes help to keep the pigment in suspension. Example Barium sulphate, calcium carbonate, magnesium carbonate etc.

Solvents are the oils used to thin the paints, increase the spread and are also known as thinners. Example-Spirit, naphtha and turpentine oil.

The fineness modulus is a numerical index of fineness which represents the mean size of the particles present in the aggregates.

As per IS 2386 (Part - I) - 1963, sieves used in calculating fineness modulus are:

80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 μm, 300 μm and 150 μm.

Counting the sieve from finest one to identify the sieve corresponding to the fineness modulus of the sample.

For fineness modulus of 3.0, corresponding sieve is 600 μm.

Gauged mortar: It is a mixture of cement, lime, sand and water. The process of adding cement to lime mortar to improve its quality is termed as gauging and mortar thus prepared is known as gauged mortar.

Lightweight mortar: It is the type of mortar which is prepared by mixing saw dust, rice husk, jute fibers, coirs, asbestos fibers etc. along with sand and lime or cement.

Plastering thickness is marked by the Bull marks. For internal plastering 12 to 15 mm will be the average thickness. Plaster thickness, Plump, wall lines & right angles are considered while fixing Bull marks.

Bench mark is the point on the ground whose reduced level is known to us.

Kiln seasoning: Kiln is an airtight chamber, timber to be seasoned is placed inside it then fully saturated air with a temperature 35°C to 38°C is forced in the kiln. The heat gradually reaches inside timber. Then relative humidity is gradually reduced, and temperature is increased, and maintained till desired degree of moisture content is achieved. This method is used for seasoning on a larger scale for rapid seasoning.

Boiling: In this method timber is immersed in water and then water is boiled for 3 to 4 hours. Then it is dried slowly. Instead of boiling water hot steam may be circulated on timber. The process of seasoning is fast, but costly.

Air and water seasoning of timber are the natural process of seasoning.

Soundness of cement is affected by the presence of excess lime (CaO) in the cement. This excess lime hydrates very slowly and forms slaked lime that occupies a larger volume than the original free calcium oxide.

The slow hydration process, therefore, affects the properties of hardened concrete. The difference in the rate of hydration of free lime and slaked lime leads to change in volume of hardened concrete. The cement which exhibits this type of volume changes is described as unsound cement.

Shakes: Shakes are nothing but cracks which separates the wood fibres partly or completely. Depending upon the type of prevailing condition, different types of shakes are formed such as Cup shakes, Heart shakes, Ring shakes, Star shakes and Radial shakes.

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.

Knots: Knots are the most common defects caused due to natural forces. During the growth of a tree, branches close to the ground or lower branches die. Bases of those branches remain in the tree as the trees grow. These bases may create imperfection known as knots.

Twisted fibres: These are known as wandering hearts and caused by twisting of young trees by fast blowing wind. The timbers with twisted fibres are unsuitable for sawing.

The revised estimate is a detailed estimate for revised quantities and the rate of items of works originally provided in the estimate without material deviation of a structural nature from the design originally approved for a project.

It is required to be prepared for the following reasons:

i) When a sanctioned estimate is likely to exceed by more than 5% either from the rates being found insufficient or from cause whatsoever except important structural alteration.

ii) When the expenditure of works exceeds or is likely to exceed by more than 10% of the administrative approval (for work more than ₹5 lakhs/-)

iii) When there are material deviations from the original proposal but not due to the material deviation of structural nature.

iv) When it is found that the sanctioned estimate is more than the actual requirement.

Rateable value: It is the net annual letting value of a property, which is obtained after deducting the amount of yearly repairs from the gross income.

Annuity: It is the annual periodic payments for repayments of the capital amount invested by a party.

Capitalised value: It is the amount of a money whose annual interest at the highest prevailing rate of interest will be equal to the net income from the property.

i) For fully glazed or gauged door, multiplying factor should be 0.80.

ii) For Flush door, multiplying factor should be 1.20.

iii) For Roof battens, multiplying factor should be 0.80.

iv) For steel rolling shutter’s, multiplying factor should be 1.10.

Sometimes a lump - sum rate is provided for certain small items for which detailed quantities cannot be taken out easily or it takes sufficient time to find the detail such as front architectural or decoration work of a building, fire place, site cleaning, dressing, Electrical installation and Contingencies etc.

Plastering of wall can be accurately measured that’s why it is not included in lump - sum items.

Work order: This is a contract and specifies the approximate quantities of different items of work, detailed specifications of each item of work, time for completion of the whole work, penalty etc. Small work up to Rs. 2,000 may be carried out by work order.

Cost plus percentage contract: In this type of contract, contractor is given certain percentage over the actual cost of the construction as his profit. Contractor arranges materials and labour at his cost and keeps proper account and he is paid by the department or owner the whole cost together with certain percentage, say 10% as his profit as agreed upon beforehand.

One m³ of mild steel weighs about 7850 kg

For 15 m³ of mild steel:

Weight = 15 × 7850 = 117750 kg

Outgoings are the expenses which are required to be incurred to maintain the revenue of the building. The various types of the outgoings are as follows:

i) Taxes: Municipal tax, Property tax, Wealth tax etc

ii) Repairs

iii) Management and collection charges

iv) Sinking fund

v) Loss of rent

vi) Miscellaneous: This includes electric charges for running lift, pump, for lightning common places etc

Note: Capital cost is the total cost of construction including land, or the original total amount required to possess a property. It is the original cost and does not change.

Capitalised value (V) of the property is given by:

V = Net income x Year purchase

Year purchase = 100/7.5 = 13.33

Net income = Rs. 1150

V = 1150 × 13.33 = Rs. 15333.33

i) Chief engineer has full power to technically sanction the work with no limits.

ii) Superintendent engineer has power to technically sanction the work up to rupees 1 crore.

iii) Executive Engineer has power to technically sanction the work up to rupees 40 lakhs.

iv) Junior Engineer has no power to technically sanction the work.

Remember the following test:

Spire test: It is a test carried out to remove Error due to non-perpendicularity of the horizontal axis and the vertical axis in surveying Instrument.

Crosshair ring Test: This test is done to make the vertical crosshair lie in a plane perpendicular to the horizontal axis.

Plate level Test: This test is done to make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical

Vertical arc Test: This test is done to make the vertical circle indicate zero when the line of sight is perpendicular to the vertical axis.

Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight.

The temporary adjustments of a theodolite are:     

i) Setting over the station 

ii) Levelling up     

iii) Elimination of parallax

Elimination of parallax:

Focusing the eye-piece: To focus the eye-piece for distinct visions of the cross-hairs, hold a sheet of white paper in front of objective and move eyepiece in and out till the cross hairs are seen sharp and distinct.  

Focusing the objective: The Telescope is now directed towards the object to be sighted and the focusing screw is turned till the image appears clear and sharp.

Substance bar: A horizontal bar used in the subtense system of surveying by tacheometry. It is held at a distant point and its distance is calculated from its known length and the angle that it subtends at the observer's eye.

Tacheometry is one of the methods used in surveying to accurately measured the horizontal distance between two inaccessible points on the ground.

Horizontal distance from instrument station and ground point is given by:

D = ks + c

Where,

k = multiplying constant

i = stadia interval

f = focal length of the objective

k = f/i

c = additive constant

c = f + d

Number of links in 30 m chain is = 150

For 1 meter run,

Number of links per meter run = 150/30 = 5

Note: Number of links in 20 m, 10 m and 5 m chain is also 5.

Length in map = 0.12 m

Breadth in map = 0.07 m

Map area = 0.07 × 0.12 = 8.4 × 10^-3

Field area = 33600 m²

Representative scale = 

Porosity (η) is defined as the ratio of volume of voids to the total volume of the soil sample in a given soil mass.

The porosity of soils can vary widely.

The porosity of loose soils can be about η = 50 to 60%.

The porosity of compact soils is about η = 30 to 40%.

If the sand is in its densest state, then

e_o = e_min

Bulk density of partially saturated soil sample is given by:

Using the relation,

Se = wG

γ = 2.0 gm/cc

G = 2.65

The coefficient of Gradation is also known as the coefficient of curvature and It is given by