Rajasthan Public Service Commission (RPSC) Rajasthan RPSC State and Sub. Services Combined Competitive Exam 2023 - Job and Vacancies

#Opportunitis and Vacancies

 
Dear Students 
Rajasthan Public Service Commission (RPSC)  Rajasthan RPSC  State and Sub. Services Combined Competitive  Exam 2023 
 
TOTAL POST: 905 
 
POST NAME: 
1. Rajasthan State Service Exam 
2. Rajasthan Subordinate Service 
 
 
EDUCATIONAL QUALIFICATIONS: 
Bachelor Degree in Any Stream from 
Recognized University in India 
AGE LIMIT 
21- 40 Years 
Age relaxation as per Norms 
 
SELECTION PROCESS 
Written Exam: 
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General: 600/- 
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Find Initial and Final Setting Time of Cement

Type of cement	Initial Setting Time (min)	Final Setting Time (min)
Ordinary Portland Cement	30	600
Portland Pozzolona Cement	30	600
Quick Setting Cement	5	30
Rapid Hardening Cement	30	600
High Alumina Cement	30	600
Sulphate Resisting Cement	30	600
Super Sulphated Cement	30	600
Portland Slag Cement	30	600
Hydrophobic Cement	30	600
Low Heat Cement	60	600
Masonry Cement	90	1440

How to Find Initial and Final Setting Time of Cement
Setting Time Test of Cement

What is initial and final setting time of cement?

Setting time of cement is an important property to knowing the time limit for handling, transportation and placing of concrete. Setting time of cement is divided into two types-

Initial Setting Time of Cement.Final Setting Time of Cement.

But before discussing these types let's understand what is a setting of cement is?

What is the setting of cement?-

When water is added to cement it reacts with water and forms a paste. This cement paste is in a plastic state and can be moulded to any shape. After some time this cement paste starts losing its plasticity and starts to set. This entire process is called the setting of cement.

What is Initial Setting Time of Cement?

Initial setting time is a time from the moment water is added to the cement, to the time that the paste starts losing its plasticity.

Initial setting time of ordinary portland cement (OPC) is 30 minutes.

What is Final Setting Time of Cement?

The time from when water is mixed with cement to the time when cement paste loses completely its plasticity and became hard is called the final setting time of cement.

Final setting time of ordinary portland cement (OPC) is 600 minutes.

Significance of Initial and Final Setting Time of Cement –

Initial setting time of cement gives us an idea about the time limit for handling, transportation and placing of cement on site.After placing cement on site it should not be disturbed up to the period of final setting time of cement.The final setting time of cement plays an important role in the formwork removal period of any structural member.

How to Calculate Initial Setting Time and Final Setting Time of Cement-

We are going to do a setting time test on cement using VICAT Apparatus as per IS 4031(Part 5):1988

APPARATUS-

VICAT Apparatus conforming to IS : 5513-1976.

VICAT mould

Measuring Cylinder of 200ml

Weighing balance with 1g accuracy

Stopwatch

Trowel

Apparatus for initial and final setting time test of cement

Procedure to Find Initial Setting Time of Cement –

1) Take 500g of cement in-tray.

2) Add the amount of water (which is calculated using the formula given below) to cement to make cement paste and start the stopwatch. ( Stopwatch should be started from the moment water is added to the cement).

Amount of water to add = 0.85P % of the weight of cement.

Where P = Percentage of water required to make a cement paste of standard consistency.

3) Pour this cement paste into the Vicat mould using a trowel within 2-3 minutes from water added to cement and level the top surface properly.

4) Then place this mould on the Vicat apparatus under the square needle.

5) Move the needle slowly downwards until the needle touches the top surface of the mould.

6) Then released the square needle and allow it to penetrate into the mould.

7) Now note down the reading on the Vicat scale, initially, it shows zero reading because the needle completely penetrates into the mould.

8) Repeat this procedure at 2 minutes intervals until the Vicat scale shows a reading of 5mm (which means the plunger should stop penetrating 5mm from the bottom of the mould).

9) Now note down the time shown on the stopwatch. This time from the moment water was added to cement to the time needle penetrated the cement mould 5mm from the bottom is theinitial setting time of cement.

Procedure to Find Final Setting Time of Cement –

1) Replace the needle of Vicat apparatus by needle with angular attachment.

2) Move the needle slowly downwards until it touches the top surface of the mould gently.

3) Then released the needle and allowed angular attachment of the needle to make an impression on the top surface of the mould.

4) Now repeat the same procedure at some time intervals until the angular attachment of the needle is failed to make an impression on top of the mould.

5) Note down the time shown on a stopwatch. This time from the moment water is added to the cement to the time at which the circular attachment of the needle failed to make an impression on the surface of the mould is called the final setting time of cement.

Calculations –

Weight of cement sample = …….. gms.

Water required to make cement paste of standard consistency = P = …….. %.

Quantity of water added = 085P = ……. ml.

Sr.NoTimeReading(mm)

The initial setting time of the cement sample is ………..

The final setting time of the cement sample is ………….

Precautions –

Lumps should be removed from the cement sample.Test should be performed away from any vibrations and disturbance.The room temperature should be maintained at 27 ± 2°C at the time of conducting the initial and final setting time of the cement test.The relative humidity of the laboratory should be 65 ± 5%.The needle should be released gently.

FAQs on Initial and Final Setting Time of Cement-

What is the initial and final setting time of ordinary portland cement(OPC) of different grades?

OPC Grade -IST FST
Grade 33     30  600
Grade 43     30  600
Grade 53     30  600

Which IS CODE is used to find initial and final setting time of cement?

The initial and final setting time of cement is calculated using the VICAT apparatus as per IS 4031(Part 5):1988.

What is the difference between the setting and hardening of cement?

The setting of cement is the stiffening process of cement paste. When we add water to the cement sample it forms a paste. This cement paste is in a plastic state. The transformation of the cement paste from a plastic state to a solid state is the setting of cement.

After the setting of cement, it starts to gain strength, this strength gaining process is called the hardening of the cement.

Table of Contents

• What is initial and final setting time of cement?
• What is the setting of cement?-
• What is Initial Setting Time of Cement?
• What is Final Setting Time of Cement?
• Significance of Initial and Final Setting Time of Cement –
• How to Calculate Initial Setting Time and Final Setting Time of Cement-
• APPARATUS-Procedure to Find Initial Setting Time of Cement –
• Procedure to Find Final Setting Time of Cement –
• Calculations –
• Precautions –
• Initial and Final Setting Time of Cement of Different Grades –
• FAQs on Initial and Final Setting Time of Cement-
• What is the initial and final setting time of ordinary portland cement(OPC) of different grades?
• Which IS CODE is used to find initial and final setting time of cement?
• What is the difference between the setting and hardening of cement?
• initial and final setting time of cement?

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Kerala Public Service Commission (KPSC) invites the application Online Form for various recruitment - Jobs & Opportunities

#Opportunities and Jobs
 
Dear Student 
Kerala Public Service Commission (KPSC) 
invites the application Online Form for various 
recruitment 
 
TOTAL POST: 114 
 
POST NAME: 
Assistant Engineer/Head Draftsman 
 
DISCPLINE 
1. Civil Engineering 
 
EDUCATIONAL QUALIFICATIONS: 
Degree in Engineering from a Recognized 
University in India on Regular Basis. 
 
 
PAY SCALE 
Scale pay of Rs.55, 200-1, 15,300/-  
 
HOW TO APPLY 
Mode: Online 
Start Date: 15-06-2023 
Last date: 19-07-2023 
 
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Chain Survey - Introduction and Condition for its use - Civil Engineering

Chain Survey - Introduction and Condition for its use 

Chain Survey

• Chain surveying is the simplest method of surveying.
• Measurements for this survey are taken on the field and other supplementary works like plotting and calculations are carried out in office.
• The measurements in chain surveying are linear.
• Chain, tape, ranging rod, arrows and, cross staff are the tools required for chain surveying.
• It is used when plans are required on a large scale.

It can be used if the area meets the following conditions:

• 1. The area shall be fairly small.
• 2. The ground is fairly levelled and open with simple details
• 3. The area needs to be open.

For more

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Other Important Topic Related to Surveying in Civil engineering

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Temporary Adjustment of SURVEYING Instrument in Civil Engineering

Temporary Adjustment of SURVEYING Instrument in Field

• The adjustments to be made at every setting of the instrument are called temporary adjustments.

• Following are the five temporary adjustments are required:

• 1. Setting up: Tripod stand is set on the ground firmly so that its top is at a convenient height.

• 2. Centering: It is done to place the vertical axis exactly over the station mark

• 3. Levelling: The levelling is done to make the vertical axis of the instrument truly vertical or to make horizontal plate truly horizontal

• 4. Focusing the eye piece: The eye piece is focused to make the cross hairs distinct and clear

• 5. Focusing the objective: This is done to bring the image of the object in plane of the cross hairs

Other Important Topic Related to Surveying in Civil engineering

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Surveyor compass versus Prismatic Compass -  Compass used in Surveying

COMPASS USED IN SURVEYING

Parameter	Surveyor’s  Compass	Prismatic Compass
Magnetic Needle	Edge bar needle is  used and it act as index	Broad needle is used  and it is hidden below the aluminium ring  and does not act as index.
Graduation	Graduated ring is attached  to the box and ring rotates with box. Graduations vary from 00 to 900  in the four quadrants.  Zero points are marked with N and S.	Graduated ring attached to the needle and remains stationary. Graduations vary from  00 to 3600 clockwise  with zero at south end.
Sighting Vanes	Readings are taken by directly looking  through the glass  and reading the north end of needle.	Readings are taken  through the vertical  side of the prism provided  at the eye vane.
Reading	Sighting and reading are done separately  and that too from different positions. After sighting the object,  the observer move around and takes the reading at North end of needle.	Sighting and reading  are done simultaneously.
Support-Requirement	Tripod is compulsory.	Tripod may or may not be used.

Other Important Topic Related to Surveying in Civil engineering

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Types of Chain and its length for Surveying work in Civil Engineering

TYPES OF CHAIN FOR SURVEY WORK AND CIVIL ENGINEERING STUDENTS

TYPES OF CHAIN

S.No.	Type of chain	Length	No. of links	Length of links
1	Meter Chain	20 m or 30 m	100 or 150	20 cm
2	Engineering Chain	100 ft	100	1 ft
3	Gunter Chain	66 ft	100	0.66 ft
4	Revenue Chain	33 ft	16	2116$\mathrm{2 }\frac{\mathrm{1/}}{16}$ ft

(As 1 foot = 0.3048 m)

66 feet = 0.3048 × 66 m = 20.11 m

 Gunter’s chain is 20.12 m long.

Other Important Topic Related to Surveying in Civil engineering

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Properties of First class brick

Properties of First class bricks

Properties of first-class bricks are given below:

• Dry first-class bricks should not absorb water more than 20% of their own weight when immersed in water for 24 hours.
• No impression should be left on the brick when a scratch is made by finger nail.
• They emit a clear ringing sound when two bricks are struck by each other.
• First-class bricks are table molded and they are burnt in Kilns.
• These are well burnt in kilns.
• The surface of the first-class brick should be smooth and rectangular.
• The edges of the brick are perpendicular (Make an angle of 90°) to the adjoining edges.
• They are regular in shape and size with sharp edges and corners.
• They shall be of uniform deep red color.
• They should be free from any cracks.
• They should be free from chips, efflorescence, flaws, and lumps of any kind.
• The average compressive strength of the first-class bricks should not be less than 100 kg/cm2 and not more than 125 kg/cm2.

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Storage of Cement Bags on Site, How to -

Storage of Cement How to Store Cement Bags on Site

Storage of Cement Bags on Site

Storage of cement bags on site should be done in a proper way. Because cement is climate-sensitive material and it reacts with moisture from the atmosphere and starts the hydration process which makes cement hard.

So there are some precaution should be taken for bulk storage of cement as per IS code 4082: 1996 as follows –

1) Sheds for storage of cement –

2) Arrangement of Cement Bags –

3) Storage Duration –

4) Protection in Rainy Season –

5) Handling of Cement Bags –

6) Use of Cement Bags –

1) Sheds for storage of cement –
On construction site storage of cement should be done in a proper way so they are not exposed to the atmosphere and can be stored for a long time before being used in construction.

Bulk Storage of cement bags on site should be done in buildings or closed sheds whose floor, roof, and walls should be dry, leakproof, and moisture-proof.

The building or shed should have a minimum number of windows and doors. The windows of these sheds are must be small in size and the door should be airtight and kept these doors closed as far as possible.

Proper drainage should be provided for the drainage of water in any case.

2) Arrangement of Cement Bags –

Before the storage of cement bags on site ensure that the shed is completely dry from inside.

Dampness is also responsible for the moisture in cement.

So, the cement bags should be stored on wooden pallets in such a way that as to keep about 150mm to 200mm above the ground level.

Wooden Pallet

Cement bags should be arranged one above the other in a cross arrangement in length-wise and cross-wise fashion to minimize the danger of toppling over.

The arrangement of cement bags should be closed to each other to avoid air circulations.

Cement Bags Arranged on Wooden a Pallet

Stacked bags should be at least 600mm away from the external walls.

These stacked cement bags should not be more than 10 bags in height to prevent the possibility of lumping up under pressure and the width of the stack should not be more than 4 bagsor 3 meters.

Different types of cement should be stored separately.

Different types of packaging bags should be stored separately such as paper bags, gunny bags, and polyethylene bags, etc.

A passage width of 600mm should be provided for easy access.

Section of Shed

Plan of Shed

3) Storage Duration –

Time is also an important factor in the storage of cement. Because the strength of cement is decreased with time.

The table below shows the percentage of decrease in strength of cement with time –

So, Cement should be used before 3 months from the date of manufacturing.

If cement is stored for more than 3 months duration then it is recommended to cement should be tested before using it on site.

4) Protection in Rainy Season –

During monsoon season extra moisture is present in the atmosphere which required extra precautions for the storage of cement.

In the rainy season, cover the stack cement bags with plastic sheets or tarpaulins to protect them from moisture and an accidental sprinkle of water.

5) Handling of Cement Bags –

Do not use hooks while handling cement bags in loading and unloading.

Do not drop cement bags from height as this can damage the packing of cement.

Handle cement bags with care to avoid split of bags and damage of packing.

6) Use of Cement Bags –

Cement bags should be used on a first in first out basis. This means cement bags that are stored first in sheds should be used first for the construction.

A label of the date of receipt of cement should be put on each stack to know the age of cement.

FAQ on storage of cement bags on site –

How long cement can be stored?

It is recommended that cement should not be store for more than 3 months.

How much area required for storage of cement?

Approximately, in 1 cubic meter, 20 cement bags of 50kg each can be stored

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15 Different Types of Cement in India and Their Uses

15 Different Types of Cement in India and Their Uses

In this article, we are going to learn about different types of cement in India, their contents, and their applications in different types of construction work.

As we know cement is the main constituent of concrete which act as a binder. Cement is made from lime, silica, alumina, magnesia, iron oxide, calcium sulphate, alkaline, etc.

By changing the percentages of this constituent of cement the properties of cement like setting time, strength gaining process, colour, resistance against chemical attack, etc. also changes and different types of cement are formed. So it is important to learn the different types of cement in Indiaand choose the right cement for construction.

15 Different Types of Cement In India

1) Ordinary Portland cement (OPC)

2) Portland Pozzolana Cement (PPC)

3) Rapid Hardening Cement –

4) Extra Rapid Hardening Cement-

5) Low Heat Portland Cement-

6) Quick Setting Cement-

7) Sulphate Resisting Portland Cement-

8) High Alumina Cement-

9) Blast Furnace Slag Cement-

10) White Cement-

11) Coloured Cement-

12) Hydrophobic Cement-

13) Air Entraining Cement-

14) Expansive Cement –

15) Waterproofing Portland cement

1) Ordinary Portland Cement

Ordinary Portland Cement

Ordinary portland cement (OPC) is the most commonly used cement worldwide. It is also known as basic Portland cement. It has good strength against cracking and dry shrinkage.

Ordinary Portland cement is available in three grades-

33 grade

43 grade

53 grade

Where the number denotes the strength of the cement after 28 days.

For example, 33 grade OPC has a strength of 33 MPa at 28 days.

Ordinary portland cement (OPC) is used for all types of construction except where a chemical attack is possible.

2) Portland Pozzolana Cement (PPC)

Portland Pozzolana Cement is manufactured by grinding 10-25% of pozzolanic material with ordinary portland cement clinkers. Pozzolanic materials include fly ash and Calcinated clay.

PPC is found to have-

High tensile strengthHigh water tightnessHigher resistance against the attack of chlorides and sulphates.It is low-heat cement.

It takes more time for strength gain as compared to ordinary portland cement (OPC). Hence, it can be used where ordinary portland cement is used Except where early strength is required.

3) Rapid Hardening Cement

As the name suggests rapid hardening cement is gaining strength quickly as compared to OPC.

Rapid hardening cement is manufactured by increasing the C₃S (Tri-calcium silicate) percentage and lowering the C₂S (Di-calcium silicate) percentage in the content of cement.

The strength of Rapid hardening cement at 3 days is same of 7 days strength of ordinary Portland cement (OPC).

Rapid hardening cement is used where high early strength is required like high-traffic road construction.

4) Extra Rapid Hardening Cement

Extra rapid hardening cement is a modified version of rapid hardening cement. This is manufactured by adding 2% of calcium chloride with rapid hardening cement.

When Extra rapid hardening cement is mixed with water it releases a huge amount of heat for a short period of time. Hence, extra rapid hardening cement is preferred to be used in cold-weather constructions.

One or two day's strength of extra rapid hardening cement is 25% more than rapid hardening cement.

It is used for high-traffic road construction. It is also used where the formwork needs to remove early.

5) Low Heat Portland Cement

Low heat portland cement has less lime content than OPC. This type of cement is manufactured by lowering the C₃S content and increasing the C₂S content.

This type of cement produced less heat of hydration and is used in mass concreting work like gravity dams, large raft slabs, etc.

Low-heat portland cement offers 20% lesser heat of hydration than OPC

6) Quick Setting Cement

As the name suggests quick setting cement is set faster than ordinary portland cement (OPC).

This type of cement is manufactured by adding aluminium sulphate and reducing the gypsum amount in cement content.

Quick-setting cement is used for construction where quick setting in a short time period is required like underwater constructions.

7) Sulphate Resisting Portland cement

This type of cement has good resistance against sulphate attack on concrete. This type of cement is manufactured by lowering tricalcium aluminate (C₃A) below 5% in cement content.

This type of cement is used where concrete is subjected to sulphate attack such as the construction of a foundation where soil or groundwater has 0.2% to 0.3% g/l sulphate salts respectively.

8) High Alumina Cement

This type of cement is manufactured by adding high alumina to the cement content. Alumina content should be a minimum 32% and the ratio of alumina to lime should be between 0.85 to 1.30.

This type of cement has high ultimate strength and high resistance against acid and high temperature.

It is used for marine construction, chemical plants, sewer construction and structure which are subjected to high temperatures like workshops, and furnaces.

9) Blast Furnace Slag Cement

Blast furnace slag cement is manufactured by replacing a portion of Portland cement clinkers with blast furnace slag. Hence, it is cheaper than Ordinary portland cement (OPC).

What is blast furnace slag?

Blast furnace slag is the by-product in iron production in blast furnace.

Blast furnace slag cement possesses lower permeability and high durability.

This type of cement is used for construction which requires low heat of hydration. It is also used for mass concreting works like the construction of dams.

10) White Cement

White cement is manufactured by lowering the content of iron oxide in ordinary portland cement.

This type of cement has the same properties as ordinary portland cement. This type of cement is costly and is used for architectural purposes like terrazzo surfaces and decorative work.

11) Coloured Cement

Coloured cement is manufactured by adding 5-10% of pigments to ordinary portland cement content.

It is also called as colcrete.

This type of cement is used for decorative works.

12) Hydrophobic Cement

Hydrophobic cement is manufactured by adding water-repellent film substances such as oleic acid and stearic acid with ordinary portland cement clinkers.

These acids form a layer around cement particles to protect them from the hydration process during transportation or the long storage of cement. This layer breaks when cement is mixed with aggregates.

This type of cement is used in construction under wet climate conditions.

Hydrophobic cement is more expensive than OPC.

13) Air Entraining Cement

This type of cement is produced by adding air-entraining agents such as resins, glues, and sodium salts to ordinary portland cement clinkers.

This type of cement is used for sulphate resistance, deicer-scaling resistance, resistance to alkali-silica reactivity and to improved workability.

14) Expansive Cement

OPC shrinks during the setting of concrete and also after the setting process concrete made up of OPC shrinks for a long period of time. But expansive cement shows the property of increasing in volume after the setting of cement which reduces the shrinkage losses.

Expansive cement is further classified as –

K Type Expansive CementM Type Expansive CementS Type Expansive Cement

15) Waterproofing Portland cement

This type of cement is manufactured by grinding water-repellent materials with Portland cement clinkers

Waterproof Portland cement is used for the construction of foundations, basements, water tanks, swimming pools, etc.

Watch the video for a better understanding of the different types of cement in India.

FAQs on Different Types of cement in India –

What is I.R.S T-40 Cement?

As we learn different types of cement in India which are commonly used in construction. But I.R.S T-40 cement is a special type of cement which is used by the Indian railway for manufacturing concrete sleepers.

This type of cement is produced by fine grinding the cement clinkers and increasing the proportion of C₃S in order to attain early strength.

What is the difference between 33 grade, 43 grade and 53 grade?

Actually these are the types of OPC according to compressive strength of cement at the age of 28 days. 33, 43 and 53 are the numbers that show the compressive strength of OPC at 28 days.

Which cement is best for concrete?

As we discussed above, different types of cement in India are available which are used according to requirements on construction sites. For regular building construction works OPC 43 grade is suitable for plain concrete and OPC 53 grade is good for reinforced cement concrete.

What is MPa in cement grade?

MPa means mega-pascals which is used to measure compressive strength.

MPa = N/mm2

Which cement is used for house construction in India?

Ordinary portland cement(OPC) and Pozzolana portland cement(PPC) are the most commonly used for construction in India.

Table of Contents

15 Different Types of Cement In India
1) Ordinary Portland Cement
2) Portland Pozzolana Cement (PPC)
3) Rapid Hardening Cement
4) Extra Rapid Hardening Cement
5) Low Heat Portland Cement
6) Quick Setting Cement
7) Sulphate Resisting Portland cement
8) High Alumina Cement
9) Blast Furnace Slag Cement
10) White Cement
11) Coloured Cement
12) Hydrophobic Cement
13) Air Entraining Cement
14) Expansive Cement
15) Waterproofing Portland cement

FAQs on
Different Types of cement in India –

What is I.R.S T-40 Cement?

What is the difference between 33 grade, 43 grade and 53 grade?

What is MPa in cement grade?

Which cement is used for house construction in India?

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