In-Depth Look at Lime's Influence on Cement and Concrete

Introduction

We are familiar with lime. Lime is a versatile material that plays a significant role in various applications, including construction, agriculture, and industry. 

 

There are two primary types of lime: 

• Quicklime (calcium oxide, CaO) and hydrated lime (calcium hydroxide, Ca(OH)2).

Here are some key points about lime:

1. Production of Lime:

•    Quicklime is produced by heating limestone (calcium carbonate, CaCO3) in a kiln. The process, known as calcination, involves removing carbon dioxide from the limestone, leaving behind calcium oxide.
•    Hydrated lime is obtained by adding water to quicklime, causing it to undergo a hydration reaction. This results in the formation of calcium hydroxide.

2. Use in Construction:

•    Lime has been historically used in construction as a mortar for masonry and plaster in buildings. Lime mortar is known for its workability and flexibility.
•    It reacts with carbon dioxide in the air over time, turning back into calcium carbonate and providing additional strength to the construction material.

3. Soil Stabilization:

• Lime is often used to stabilize soil in construction projects. 
• It helps improve the engineering properties of soil, enhancing its strength and reducing plasticity.

4. Water Treatment:

• Hydrated lime is used in water treatment processes to adjust pH levels and remove impurities.

5. Agricultural Applications:

• Agricultural lime, which is primarily composed of calcium carbonate, is used to improve soil quality by neutralizing acidic soils and providing essential nutrients to plants.

6. Industrial Processes:

•  Lime is utilized in various industrial processes, including the production of chemicals, paper, and metals.

7. Environmental Benefits:

•  Lime can be used to reduce sulfur dioxide emissions in industrial processes and in flue gas desulfurization systems in power plants.

Lime's properties make it a valuable material in a range of applications, contributing to the strength and stability of construction materials and providing environmental and agricultural benefits.

 

 

Connection Between Lime and Cement

Lime and cement are both important materials in construction, and they have a historical relationship in the development of construction techniques. Here are some aspects of the relationship between lime and cement:

1. Historical Context:

•  Lime has been used in construction for thousands of years. Ancient civilizations, such as the Romans, used lime-based mortars and concrete in their structures.
• The Romans used a form of natural cement, which contained lime and volcanic ash, to create structures like the Pantheon and aqueducts.

2. Lime in Traditional Mortars:

• Before the widespread use of Portland cement, lime mortars were commonly employed in construction. 
• These lime mortars were known for their flexibility and ability to accommodate movement in masonry structures.

3. Introduction of Portland Cement:

• Portland cement, a key component of modern concrete, was developed in the 19th century. 
• It gained popularity due to its rapid setting and strength development compared to traditional lime-based materials.

4. Hydraulic Lime:

• Hydraulic lime is a type of lime that sets and hardens through a chemical reaction with water, similar to cement. 
• It is often used in restoration projects and applications where a more flexible and breathable material is desired.

5. Combined Use in Mortars:

• In some cases, lime and cement may be combined to create mortars with specific properties. This combination can provide a balance between the flexibility of lime and the strength of cement.

6. Historic Preservation:

• Lime is still widely used in the restoration and preservation of historic buildings. 
• It is chosen for its compatibility with older masonry materials and its ability to allow for natural moisture movement within the structure.

7. Soil Stabilization:

• Both lime and cement are used for soil stabilization, but they offer different advantages. 
• Lime is often preferred in situations where a more gradual and less rigid improvement is required.

8. Sustainability Considerations:

• Lime production generally has a lower environmental impact compared to cement production. 
• Lime-based materials can be more environmentally friendly, making them suitable for sustainable construction practices.

In summary, while cement, especially Portland cement, has become the predominant binder in modern concrete, lime continues to have a role in construction, particularly in specialized applications, historic preservation, and sustainable practices. The choice between lime and cement often depends on the specific requirements of a construction project and the desired properties of the material. 

Role of Lime on Cement functioning

Lime plays a crucial role in cement production, specifically in the production of clinker, which is the main component of cement. The production of clinker involves the heating of a mixture of raw materials, and lime contributes to the formation of key minerals during this process. The main raw materials used in cement production are limestone (calcium carbonate), clay, shale, and silica sand.

Here's how lime is involved in cement production:

1. Calcination of Limestone:

•    - The primary source of lime in cement production is limestone (calcium carbonate, CaCO3). During the first stage of cement production, limestone is quarried and then crushed to smaller sizes.
•    - The crushed limestone is then heated in a kiln to a high temperature (around 1450°C). This process is known as calcination, and it results in the decomposition of limestone into lime (calcium oxide) and carbon dioxide.

   `\[ CaCO_3 \rightarrow CaO + CO_2 \]`

2. Formation of Clinker Minerals:

•    - The lime (calcium oxide) produced during calcination combines with other minerals present in the raw materials, such as silica, alumina, and iron oxide, to form the main clinker minerals.
•    - Tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and tetracalcium aluminoferrite (C4AF) are the primary clinker minerals formed during the high-temperature reactions in the kiln.

3. Hydration Process:

•    - After the clinker is produced, it is finely ground to form cement powder. When this cement powder is mixed with water during the construction process, it undergoes a hydration reaction.
•    - The hydration reaction involves the reaction of the clinker minerals with water to form hydrated compounds, including calcium silicate hydrate (C-S-H) and calcium hydroxide (CH).
•    - The presence of lime in the clinker contributes to the formation of these hydration products, which provide strength and durability to the concrete.

`   \[ C_3S + H_2O \rightarrow C-S-H + CH \]`

`\[ C_2S + H_2O \rightarrow C-S-H + CH \]`

  ` \[ C_3A + 3H_2O \rightarrow C-S-H + \(OH)_6 \]`
  ` \[ C_4AF + 2H_2O \rightarrow C-S-H + \(OH)_6 \]`

The role of lime in cement production is essential for the formation of clinker minerals and, subsequently, the development of strength in the final concrete. The hydrated compounds formed during the hydration process contribute to the binding properties and overall performance of the cementitious material.

Role of Calcium Hydroxide (Ca(OH)₂) during construction and cement work

• Calcium hydroxide (Ca(OH)₂) is a byproduct of the hydration reaction in cement. It forms when water reacts with the clinker minerals in cement, particularly tricalcium silicate (C₃S) and dicalcium silicate (C₂S). The role of calcium hydroxide in cement is significant and has both positive and potential drawbacks in terms of concrete performance:

1. Positive Aspects:

•    - Early Strength Development: Calcium hydroxide contributes to the early strength development of concrete. It is responsible for the initial setting and hardening of the concrete mix.
•    - Alkalinity: The presence of calcium hydroxide increases the alkalinity of the concrete. This high pH is beneficial for the passivation of steel reinforcement, providing corrosion protection.

2. Potential Drawbacks:

•    - Long-Term Strength Gain: While calcium hydroxide contributes to early strength, it is not a primary contributor to the long-term strength of concrete. Over time, calcium hydroxide can leach out of the concrete, potentially leading to a decrease in strength and durability.
•    - Cracking and Durability Concerns: Excessive amounts of calcium hydroxide can contribute to the formation of cracks in concrete, especially in situations with drying and wetting cycles. These cracks may compromise the durability of the structure.

3. Leaching and Efflorescence:

•    - Calcium hydroxide is water-soluble, and in certain conditions, it can leach out of the concrete. This leaching may result in the formation of efflorescence on the concrete surface, which is a white, powdery deposit.

4. Use in Pozzolanic Reactions:

•    - In some cases, supplementary cementitious materials (SCMs) such as fly ash or silica fume are added to concrete mixes. These materials can react with calcium hydroxide to form additional cementitious compounds, enhancing long-term strength and durability.

5. Role in Autogenous Healing:

•    - Calcium hydroxide participates in autogenous healing, a process where cracks in concrete can self-heal to some extent. The chemical reactions involving calcium hydroxide contribute to the sealing of microcracks.

In summary, calcium hydroxide is an integral part of the hydration process in cement, contributing to early strength and alkalinity. However, its potential drawbacks, such as leaching and long-term durability concerns, are important considerations in concrete mix design. Engineers and concrete practitioners often balance the benefits and drawbacks of calcium hydroxide to optimize concrete performance for specific applications.

"Lime can be used to reduce sulfur dioxide emissions in industrial processes and in flue gas desulfurization systems in power plants"

Application of lime in addressing air pollution, specifically sulfur dioxide (SO2) emissions.

Here's a breakdown of the key components of the statement:

1. Sulfur Dioxide (SO2) Emissions:
   - Sulfur dioxide is a harmful gas produced by the combustion of fossil fuels containing sulfur, such as coal and oil. It is a major contributor to air pollution and can lead to environmental and health issues.

2. Lime's Role:
   - Lime, or calcium oxide (CaO), can be used in industrial processes and power plants to reduce sulfur dioxide emissions.

3. Flue Gas Desulfurization (FGD) Systems:
   - Power plants often use flue gas desulfurization systems to control and reduce sulfur dioxide emissions from the combustion of fossil fuels.
   - In these systems, lime is commonly used as a reagent in a process known as "flue gas desulfurization" or "scrubbing."

4. Flue Gas Desulfurization Process:
   - The flue gas, which contains sulfur dioxide, is passed through a system where lime is introduced. Lime reacts with sulfur dioxide to form calcium sulfite (CaSO3) and, further, calcium sulfate (CaSO4), also known as gypsum.
   - The reaction is often represented as follows:
    ` \[ CaO + SO2 \rightarrow CaSO3 \]`
    ` \[ CaSO3 + 1/2O2 + H2O \rightarrow CaSO4 \cdot 2H2O \]`

5. Formation of Gypsum:
   - Gypsum is a solid byproduct that can be easily removed, and it has commercial value in various industries, such as construction and agriculture.

6. Environmental Benefits:
   - The use of lime in flue gas desulfurization helps to mitigate the environmental impact of sulfur dioxide emissions. By converting sulfur dioxide into solid gypsum, the harmful gas is removed from the flue gas, reducing air pollution.

In summary, lime plays a crucial role in reducing sulfur dioxide emissions in industrial processes, particularly in power plants equipped with flue gas desulfurization systems. The use of lime helps control air pollution, improve air quality, and mitigate the environmental impact of combustion processes that release sulfur dioxide into the atmosphere.

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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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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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Quick Revision of Cement - Civil Engineering Study vk

Cement, Mortar and Concrete

Building material Civil engineering

• Admixture used in Concrete
• Bogues Compound
• Properties of Cement
• Ordinary Portland cement OPC:
• Portland Pozzolana cement PPC:
• Rapid Hardening Cement RPC
• Amount of Water content used during Test on Cement
• Note
• High Alumina Cement HAC
• Lime-Cement Mortar
• Mortar
• mortar after it has set 
• Polymer concrete:
• Strength of concrete
• Minimum Number of concrete sample
• Durability
• Fly ash
• Workability of Concrete based on Tests
• Ferro-Cement
• Surkhi

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• a.Admixture, if used in concrete, shall comply with, IS 9103:1999
• b.An admixture is a material other than water, aggregates, or cement that is used as an ingredient of concrete or mortar to control setting and early hardening, workability, or to provide additional qualities to concrete.
• For detail knowledge of Admixtures - Click here

Plasticizer

• Plasticizers are a mixture of organic and inorganic substance which permits the reduction in W/C ratio at the same workability or ensure higher workability at the same W/C ratio.

Example:

• lignosulphate, polyglycol ester, carbohydrates, hydroxylated carboxylic acid

superplasticizer

• superplasticizer is the same as that of plasticizer in terms of their action but in chemical reaction they are different

Example:

• modified lignosulphonate, sulphonated malanie formaldehyde ( SMF ), sulphonated napthalene formaldehyde

Retarders

• Retarders are the admixture that slows down the chemical reaction of hydration so that concentration can remain plastic and workable for more duration in comparison to the concentration in which retarders not added.

Example:

• calcium sulphate, tartaric acid, starch, sugar cellulose.

Accelerators

• These are the admixture which increase the rate of gain of development of strength in concrete.

Example:

• calcium chloride, silicates, flousilicate etc.

Air-entraining admixture

• These are the type of admixtures that entrapped million of an air bubble in between the voids of the aggregate, which act as the flexible wall bearing that slips pass over each other thereby modified the properties of concrete with respect to workability, frost action, segregation, bleeding.

Example:

• Natural wood resin, plant and animal fatty oil, stearic acid, oleic acid, hydrogen peroxide, aluminium powder

TOC

• The setting and hardening of cement after addition of water is due to hydration of some of the constituent compounds of cement such as Tricalcium aluminate, Tricalcium silicate, Di-calcium silicate, and Tetra calcium alumino-ferrite.
• These compounds are known as Bogue’s Compounds.
• Major compounds of cement clinker (also known as Bogues compounds)

Bogues compounds and its Properties

Tetra-calcium alumino-ferrite(C4AF): FELITE: 10%

• Formed within 24 hours of the addition of water.
• The High heat of hydration in initial periods.
• This is called as Felite.
• The heat of hydration is 420 J/gm.
• It has the poorest cementing value but it responsible for long term gain of strength of the cement.
• Note: The rate of hydration is highest for C4AF

Tricalcium aluminates(C3A): CELITE: 12%

• Formed in 24 hours of the addition of water.
• Max. evolution of heat of hydration.
• Reduce the setting time of cement.
• Celite is the quickest one to react when the water is added to the cement.
• It is responsible for the flash setting.
• The increase of this content will help in the manufacture of Quick Setting Cement.
• The heat of hydration is 865 J/gm.
• The heat of hydration is highest for C3A.
• Celite is the quickest one to react when the water is added to the cement.
• It is responsible for the flash setting.
• It provides weak resistance against sulphate attack and contribution to the development of strength.

Di-calcium silicate(C2S): BLITE: 45%

• Last compound formed during the hydration of cement
• Responsible for progressive later stage strength
• The Proportion of this increase in hydraulic structures, bridges, etc.
• This compound will undergo reaction slowly.
• It is responsible for the progressive strength of concrete.
• This is also called as Belite.
• The heat of hydration is 260 J/gm.
• This compound will undergo reaction slowly
• A higher percentage of C2S results in slow hardening, less heat of hydration, and great resistance to chemical attack.

Tri-calcium silicate(C3S): ALITE: 50%

• Formed within a week.
• Responsible for initial strength of cement.
• Contribute about 50-60% in cement.
• This is also called as Alite.
• This is also responsible for the initial set and early strength of the concrete.
• The cement that has more C3S content is good for cold weather concreting.
• The heat of hydration is 500 J/gm.
• It undergoes hydration within one week.
• It has the best cementitious property among all the other Bogue's Compounds.
• Tricalcium Silicate (C3S) hardens rapidly
• The cement that has more C3S content is good for cold weather concreting.

Chemical Name	Formula	Notation	Percentage
Tricalcium Silicate	3CaO, SiO2	C3S	30-50
Dicalcium Silicate	2CaO, SiO2	C2S	20-45
Tricalcium Aluminate	3CaO, Al2O3	C3A	8-12
Tetra-calcium Alumino-ferrite	4CaO, Al2O3, Fe2O3	C4AF	6-10

Note

• The decreasing order of rate of hydration of Portland cement compounds is

• C4 AF > C3 A > C3 S > C2 S.

• Decreasing order of heat of hydration of Portland cement is

• C3 A > C3 S > C4 AF > C2S

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Following are parameters and properties of cement:

• 1. Bulk density of cement = 1440 kg/m3

• 2. Specific gravity of cement = 3.15

• 3. Weight of one bag of cement = 50 kg

• 4. Volume of cement bag = 50/1440 = 0.035 m3

• 5. Number of cement bags in 1 m3 = 30 approx.

• 6. Volume of dry mortar is 30% more than volume of wet mortar.

• ∴ Volume of dry mortar = 1.3 × volume of wet mortar

Cement

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Cement can be defined as the bonding material having cohesive & adhesive properties which makes it capable to unite the different construction materials and form the compacted assembly. Ordinary/Normal Portland cement is one of the most widely used types of Portland Cement. The name Portland cement was given by Joseph Aspdin in 1824 due to its similarity in color and its quality when it hardens like Portland stone. Portland stone is white grey limestone on the island of Portland, Dorset.

Low heat Portland cement:

• Low C3S and C3A and more contents of C2S
• It is use in mass concrete work
• Rate of development of strength is low but ultimate strength is same

Super Sulphated Portland cement :

• 80–85% Granulated slag + 10– 15% calcium sulphate + 5% Portland cement clinker.
• It is resistant to chemical attacks particularly to sulphate & highly resistant to sea water
• It should not be used with any admixture

 

Portland Slag cement:

• The mixture of portland cement,granulated blast furnace slag & Gypsum
• High Sulphate resistance & it is Used in mass concreting work

Quick setting cement:

• Fine grounded OPC with reduced Gypsum content & small amount of aluminium sulphate.
• Initial Setting Time (IST) = 5 minutes & Final Setting Time (FST) = 30 minutes
• Used in under water concreting.

White and Coloured Portland cement (IS: 8042) :

• From Pure white chalk, china clay & Iron Oxide should not bemore than 1%.
• These are used for making Terrazzo flooring, ornamental works & casting stones.
• Hunter scale is use for checking the whiteness of cements
• 5–10% Colouring pigment before grinding

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• This cement is produced by inter grinding the cement clinkers with 10 - 15 % of pozzolanic material.
• Pozzolanic material is essentially a siliceous compound that is itself does not possess any binding property, but when finely grinded reacts with lime released during the hydration of cement and results in the formation of a compound possessing binding property.

Effects of pozzolana in ordinary Portland cement

• Higher water tightness
• Low heat of hydration
• Reduces the cost
• Higher resistance against chemical attacks (Chloride & Sulphate)
• Higher resistance against volume change
• A slower rate of gain of strength
• Increases shrinkage
• Reduces permeability
• Reduces bleeding

TOC

• It is obtained by grinding 10% more than the OPC for greater Fineness.
• The difference of rapid hardening cement to that of ordinary Portland cement is the quantity of Limestone (tri-calcium silicate) used as raw material, which gives the high early strength to the cement.
• It attains early strength due to larger proportion of lime grounded finer than normal cement.

Properties of Rapid Hardening Cement:

• 1. It gains strength faster than OPC. In 3 days it develops 7 days strength of OPC with same water cement ratio.
• 2. Its initial setting times is 30 mins and final setting time is 600 mins which is same as OPC.
• 3. It emits more heat during setting, therefore this cement is unsuitable for mass concreting.
• 4. This cement is lighter and costlier than OPC. Its short curing period makes it economical.
• 5. This cement should be stored in a dry place, or else its quality deteriorates due to premature carbonation and hydration.

LIST OF IS:CODES RELATED TO CIVIL ENGINEERING STUDY AND CEMENT


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Type of test                           water content

Initial and Final Setting Time     0.85p

Compressive Strength                 p/4 + 3 

Tensile Strength                         p/5 + 2.5 

Soundness Test                             0.78p

 Note Where p = Standard consistency

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• Autoclave test is used to determine unsoundness due to magnesia.
• Vicat apparatus is used to determine the consistency of cement.
• Le Chatelier's flask is used to determine the specific gravity of cement.
• Le Chatelier's apparatus is used to determine the unsoundness due to lime.
• Sieve test and Blainis air permeability apparatus is used to determine the fineness of the cement.
• Low heat cement sets slower than OPC.
• Final setting time does not decide the strength of cement.
• Initial setting time of Portland PozzoIlona is 30 minutes.
• Air-induced setting is observed when stored under damp conditions.
• Calcium sulphate (CaSO4): this ingredient is in the form of gypsum and its function is to increase the initial setting time of cement.

TOC

• IT is a special cement, manufactured by mixing of bauxite (Aluminum ore) and lime (Limestone) at a certain temperature.
• The setting time of high alumina cement is greatly affected by the addition of plaster of Paris, lime, Portland cement, and organic matter. Thus, no additives should be used.
• High alumina cement is very reactive and has very high compressive strength.
• As per IS Code: 6452:1989, the maximum initial and final setting time for high alumina cement is same as ordinary cement.
• Due to the property of the cement, in actual the alumina cement has higher initial setting time but lower final setting time as compared to ordinary cement.

TOC

• In this type of mortar, lime is used as binding material.
• The lime may be fat lime or hydraulic lime.
• The fat lime shrinks to a great extent and hence it requires about 2 to 3 times its volume of sand. The lime should be slaked before use. This mortar is unsuitable for water logged areas or in damp situations.
• For hydraulic lime, the proportions of lime to sand by volume is about 1:2 or so. This mortar should be consumed within one hour after mixing. It possesses more strength and can be used in damp situations.
• The lime mortar has high plasticity and it can be placed easily.
• It possesses good cohesiveness with other surfaces and shrinks very little.
• So, lime mortar gives a fairly strong surface finish.
• It is sufficiently durable, but it hardens slowly.
• It is generally used for lightly loaded above-ground parts of buildings.
• Also known as Gauged mortar.
• It is made from cement and lime.
• The advantages of lime-cement mortar are increased Water retentivity, workability, bonding properties and frost resistance.
• This mortar gives good and smooth plaster finish and is used in buildings.

Mix proportions are given below-

Location Ratio (by volume) (Cement : Lime : Sand)

Outside walls 1 : 1 : 6 to 1 : 2 : 9
Inside walls 1 : 2 : 9 to 1 : 3 : 12

Note:-

• Since presence of lime increases the water retentivity in cement. This presence of water reduces the shrinkage of cement upon drying.

TOC

• The term mortar is used to indicate a paste prepared by adding the required quantity of water to a mixture of binding material like cement or lime and fine aggregate like sand.

Types of mortar depending on binding material are:

• 1. Lime mortar
• 2. Cement mortar
• 3. Gauged mortar
• 4. Surkhi mortar
• 5. Gypsum mortar

The requirement of a mortar before it has set:

• It should remain usable for 2 hrs after mixing
• It should be sufficiently cohesive to stay on a trowel.
• It should be sufficiently workable to spread easily.

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• It should be strong enough to carry the loads that are applied to it by the masonry units.
• It should be capable of resisting the penetration of rainwater.
• It should be capable of resisting the penetration of rainwater.
• It should not affect the durability of the materials with which it comes into contact.
• The joints formed by mortar should not develop cracks and they should be able to maintain their appearance for a sufficiently long period

Note:

• The lime mortar should be consumed within 36 hours after its preparation and it should be kept wet or damp.
• The cement mortar should be consumed within 30 minutes after adding water and for this reason, it is advisable to prepare cement mortar of one bag of cement at a time.
• The gauged mortar or composite mortar should be used within 2 hours of the addition of cement.

TOC

• Polymer concrete is a composite material in which the aggregate is bound together in a matrix with a polymer binder. The composites do not contain a hydrated cement phase, although Portland cement can be used as an aggregate or filler.The impregnation of monomer and subsequent polymerisation greatly improves some properties of the concrete.

Properties:

• a.High tensile, flexural, and compressive strengths
• b.Resistance to oil, grease, abrasion and good adhesion to most surfaces
• c.Good long-term durability with respect to cycles of freezing and thawing
• d.Low permeability to water and aggressive solutions
• e.Light weight.

Applications:

• a.Most suitable for sewage disposal works because of its high sulphate and acid resistance properties.
• b.In the production of prefabricated elements and prestressed concrete.
• c.In ferro-cement products and marine works.
• d.In nuclear power plants and industrial applications.

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• *Strength of concrete is generally tested after 28 days as concrete cube strength because concrete gains strength with time after casting. It takes much time for concrete to gain 100 % strength and the time for the same is still unknown. The rate of gain of concrete compressive strength is higher during the first 28 days of casting and then it slows down.

The below table shows the concrete compressive strength with age:

Age Strength (Percent)

• 1 day 16 %
• 3 days 40 %
• 7 days 65 %
• 14 days 90 %
• 28 days 99 %

TOC

• As per IS 456:2000, cl. 15.2.2, The minimum numbers of samples required for testing depending upon the quantity of concrete in the work is given below –

No of concrete sample

Quantity of concrete in the work, m3	Number of samples
1 – 5	1
6 – 15	2
16 – 30	3
31 – 50	4
51 and above	4 plus one addition sample for each additional 50 m3

TOC

• Durability is defined as the capability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties.

TOC

• i) Cement content and water-cement ratio of concrete
• ii) Cover to embedded steel
• iii) Shape and size of member
• iv) The Environment
• v) Type and Quality of constituent materials

LIST OF IS:CODES RELATED TO CEMENT IN CIVIL ENGINEERING

Cement content:

• Mix must be designed to ensure cohesion and prevent segregation and bleeding. If cement is reduced, then at fixed w/c ratio the workability will be reduced leading to inadequate compaction. However, if water is added to improve workability, water / cement ratio increases and resulting in highly permeable material.

• If excess cement content is used, problems like drying shrinkage, alkali-silica reaction may occur which finally effects the durability of concrete.

Curing:

• It is very important to permit proper strength development aid moisture retention and to ensure hydration process occur completely.

Permeability:

• It is considered the most important factor for durability. It can be noticed that higher permeability is usually caused by higher porosity. Therefore, a proper curing, sufficient cement, proper compaction and suitable concrete cover could provide a low permeability concrete.

Concrete

• Concrete is a composite material that is a mixture of binding materials, coarse aggregate, fine aggregate, water, and admixtures.

• Cement imparts adhesive and cohesive properties to the concrete and binds various ingredients into a compact mass.

• Coarse aggregate occupies the bulk of the volume of concrete and contributes to its strength.

• Fine aggregate act as a filler material and helps in improving the workability of concrete.
• Water causes hydration of the cement.

• Admixtures are the material that is added to the concrete to give it certain desired characteristics.

TOC

Definition

• Ash produced in small dark flecks by the burning of powdered coal or other materials and carried into the air.

Properties

• Fly ash is a pozzolanic material that is used as a replacement of cement.
• It also acts as a replacement of sand, when the sand in concrete is replaced by 10% of fly ash the concrete strength increases and thus makes concrete economical. Although if fly ash is increased beyond 10% then the overall strength of concrete decreases.
• Fly ash as a replacement of cement provides later strength to concrete.
• Initially pozzolana does not have cementious property, but when it reacts with calcium hydroxide(generated by hydrating cement) it acts as a cementitious material. Thus the early age strength provided by pozzolanic material (fly ash) cement is very less.

Range

15% - 30%

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Workability of Concrete based on Tests

Work Description	Slump (mm)	Compaction Factor	Vee-Bee time
Moist Earth	-	-	40 to 25-20
Very Dry	-	.70	20 to 15-10
Dry	0 - 25	.75	10 to 7 - 5
Plastic	25 - 50	.85 - 90	5 to 4 -3
Semi Fluid	75 - 100	.90 - .95	3 to 2-1
Fluid	100 - 150	.95 - 100	less than1

Slump Test

Degree of Workability	Slump value in mm
Very low	Less than 25
low	25-75
medium	50-100
high	75-100
very high'	100 – 150

Degree of workability	Slump mm	Compacting factor
		Small apparatus	Large apparatus
Very low compacting factor is suitable	-	0.78	0.80
Low	25 – 75	0.85	0.87
Medium	50 – 100	0.92	0.935
High	100 – 150	0.95	0.96
Very High	-	-	-

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• Ferroecement developed by P.L. Nervi, an Italian architect, and engineer, in 1940. It consists of closely spaced wire meshes which are impregnated with rich cement mortar mix.
• The wire mesh is usually of 0.5 to 1.0 mm diameter wire at 5 mm to 10 mm spacing and cement mortar is of the cement-sand ratio of 1: 2 or 1: 3 with water/cement ratio of 0.4 to 0.45.
• The ferrocement elements are usually of the order of 2 to 3 cm in thickness with 2 to 3 mm external cover to the reinforcement. The steel content varies between 300 kg to 500 kg per cubic meter of mortar.
• The basic idea behind this material is that concrete can undergo large strains in the neighbourhood of the reinforcement and the magnitude of strains depends on the distribution and subdivision of reinforcement throughout the mass of concrete.
• It is impervious in nature, has the capacity to resist shock and no formwork is required to gain initial strength.
• The main advantages are the simplicity of its construction, a lesser dead weight of the elements due to their small thickness, its high tensile strength, fewer crack widths compared to conventional concrete, easy repairability, noncorrosive nature and easier mouldability to any required shape.

TOC

• Surkhi is broken brick powder or burnt clay soil and used as a substitute for sand for concrete and mortar, and has almost the same function as of sand but it also imparts some strength and hydraulicity.

• Surkhi is used as a substitute for sand for concrete and mortar, and has almost the same function as of sand but it also imparts some strength and hydraulicity. Surkhi is made by grinding to powder burnt bricks, brick-bats or burnt clay ; under-burnt or over-burnt bricks should not be used, nor bricks containing high proportion of sand. When clay is especially burnt for making into surkhi, an addition of 10 to 20 per cent of quick lime will improve its quality ; small clay balls are made for burning.

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Civil engineering - Building Materials - mortar and Lime

 Mortar and lime

Building material Civil engineering

Mortar

Mortar is defined as the mixture containing a binding agent Like lime or cement,water and fine aggregate.

On the basis of Binding agent mortar is classified into following types

1 lime mortar

It does not set quickly

Lime mortar generally made with hydraulic Lime

Its provide better resistance against rain penetration 

It is unliable to crack when compared with cement mortar

2.Cement Mortar

It is most suitable for construction work in Water Logged area

Gives shrinkage crack

3.Gauge Mortar

It is also called as composite mortar or cement lime mortar

with proportion of 1:1:6 to 1:1:8

After addition of cement It should be used with 1 to 2 hr

4 Light weight Mortar

It is Prepared by adding the material 

like as Wood - Powder , saw-dust, etc to lime/cement mortar

5. Surkhi Mortar

Surkhi is a pozzolanic material and it is very fine in size 

and it must be pass from a 4.75 mm sieve

surkhi is added to lime mortar to give hydraulically ability to set in presence of water

Lime-Cement Mortar:

Also known as Gauged mortar.

It is made from cement and lime.

The advantages of lime-cement mortar are 

increased Water retentivity, 

workability,

 bonding properties 

and frost resistance.

This mortar gives good and smooth plaster finish and is used in buildings.

Selection of Mortar

Selection of Mortar

No	work	Proportion cement:sand
1.	Normal Brick work	1:6
2.	Plaster work	1:3 to 1:4 1:2 (lime:mortar)
3.	Pointing in m2	1:1 to 1:2
4.	Damp Proof Work	1:2
5.	Grouting	1:1.5
6.	Guniting	1:3

Note - Addition of 5% to 6% of moisture content by weight increase

the volume of dry sand from 13% to 18%

Lime

CaCO3 = CaO + CO2 

CaO + H2O = Ca(OH)2

Chart for lime reactions

no	Name	Chemical formula
1.	Limestone	CaCO3
2.	Quick lime or Lump lime	CaO
3.	Ca(OH)2	Hydrated lime or slaked lime
4.	H2o	water

When the water is added to quick lime in sufficient quantity then a Chemical

reaction take place due to which quicklime Swell, Crack and Finally we get

Hydrated lime

Types of lime

No	Type	Description
1.	Fat lime	Also known as  Pure lime, Rich lime,  White lime etc. It contains impurity less than 5% hence  It has High Calcium Oxide content It is obtained from Sea shell, Coral Reefs etc It can be used in white washing and Plastering.
2.	Hydraulic Lime	This is called water lime because it can set under water. It contain Silica, Alumina and Iron Oxide in small quantity. It can be suitable for making mortar and using in masonry construction
3.	Poor lime	It is also called Impure lime or Weak lime, lean lime It contains 30% Impurities as compared to pure Lime
4.	Milk of Lime	A thin pour able suspension of slake lime in water is called milk of lime.
5.	Note	slaked lime is utilized in painting and decorative work Hydraulic lime is obtained from Kankar Non hydraulic lime from calcined dolomite stones. Burning of limestone in presence of Oxygen is known as Calcination.

Bulking of Sand

• The increase in moisture of sand increases the volume of sand and is known as bulking of sand.
• The volume of dry sand increases due to absorption of moisture. These volume increase of dry sand is known as bulking of sand. When dry sand comes in contact with moisture, a thin film is formed around the particles, which causes them to get apart from each other. This results in increasing the volume of sand. Addition of 5% and 6% of moisture content by weight increases the volume of dry sand from 18% to 38%.

Reason for the bulking of sand

• The reason is that moisture causes the film of water around sand particles which results in the increase of the volume of sand
• Bulking structure in sand is due to capillary action.
• For a moisture content percentage of 5 to 8, there will be an increase in volume up to 20 to 40 percent depending upon the sand
• If the sand is finer there will be more increase in volume

Graphical representation of bulking of sand is shown below:

Terracotta

• It is refractory clay brick and used in ornamental parts of buildings.
• The clay used for its manufacture should be of superior quality 
• and should have sufficient iron and alkaline matters. 
• It is burnt in special furnace known as Muffle furnace.

Water needed for complete Hydration of Cement

Approximately 23% water by weight is required for hydration and 15% water is entrapped in between the voids of cement. So, the total water required for complete hydration and workability is 38% by weight.

Segregation

• As per clause 13.2 of IS 456: 2000, the maximum permissible free fall of concrete to avoid segregation may be taken as 1.5 m or 150 cm.

• Segregation can be defined as the separation of the constituent materials of concrete.

• Insufficiently mixed concrete with excess water content shows a higher tendency for segregation.

• Dropping of concrete from heights as in the case of placing concrete in column concreting will result in segregation.

Slump and compaction Factor

Consistency	Slump	Compaction Factor
Moist earth	0	0.65-0.7
Very Dry	0-25	0.7-0.8
Dry	25-50	0.8-0.85
Plastic	50-100	0.85-.95
Semi-fluid	100-175	0.95-1

Plastic asphalt 

• It is a mixture of cement and asphalt. Mechanical properties, resilient modulus, temperature susceptibility, water damage, creep and permanent deformation resistance are all improved by the mixing of cement and asphalt altogether.

• It is used for filling patches and cracks of flexible pavements. The temperature sensitiveness of the asphalt is overcome by the application of cement to it. Thus, it is primarily used for repair or reconstruction purpose.

Types of lime:

1. Fat lime: 

It slacks rapidly and its volume is increased by 2 to 2.5 times of its original volume hence, it is referred as fat lime. It is also known as pure lime, rich lime, high calcium lime. It has more than 95% purity.

Properties- Slow setting, High plasticity, Soluble in water, Vigorous slaking, Perfectly white colour

Application- White wash & Plastering

Source- Sea shells

2. Hydraulic lime: 

It is also known as water lime as it is capable of setting in water and damp condition. It has 70% to 90% purity.

Properties- Insoluble in water, Low plasticity, Less slaking, Off white colour, High hydraulicity

Application- Brick masonry or Stone masonry

Source- burning of Kankar

3. Poor lime: 

It is also known as Impure or lean lime. It has less than 70% purity.

Properties- Muddy Colour

Application- Used in brick work around foundation

Floats are used to press mortar and spread it uniformly.

A trowel is a small hand tool used for digging, applying, smoothing, or moving small amounts of viscous or particulate material. Aluminium rod is used to strike off excess mortar.

A brush is used to clean the mortar. Floats are used to press mortar and spread it uniformly.

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