PROPERTIES AND USES OF CEMENT

CEMENT:-

Cement, as a binding material, is a very important building material. Almost every construction work requires cement. Therefore, the composition of cement is a matter of great interest to engineers.

Cement is one of the oldest binding materials used for construction. Be it buildings, bridges, skyscrapers, subways, or pipelines, good quality cement is paramount for world-class infrastructure. But how do you measure the quality of cement? Are there set parameters that distinguish high quality cement from low quality cement? Well, the answer is yes. You may have heard of terms like 33 grade cement or 53 grade cement. These are terms used for describing different grades of cement. A grade of cement indicates the strength of cement that is measured in Mega pascal (Mpa) or N/mm2. Cement is usually measured after 28 days of curing for a standard cube.

USES OF CEMENT:-

Cement is a very useful binding material in construction. The applications of Cement over various fields of construction have made it a very important as a civil and construction material.

FIELD TEST OF CEMENT :-

Sometimes it may be required to perform cement quality tests at a site within a very short period of time for evaluating the condition of the supplied cement.

WHITE PORTLAND CEMENT:-

White Portland cement, as the name indicates, is a kind of cement with white color. It is the same as ordinary gray Portland cement except in respect to color and fineness.

PROPERTIES OF A GOOD CEMENT:-

It is always desirable to use the best cement in constructions. Therefore, the properties of a good cement must be investigated. Although desirable cement properties may vary depending on the type of construction.

Comparison of Red Clay Bricks and Fly Ash Bricks

Comparison of Red Bricks and Fly Ash Bricks

 

Properties


Red Bricks/Clay        Bricks

 

 

Fly Ash Bricks

 

Remarks

Density 1600-1750 kg/m3 1700-1850 kg/m3 Higher load-bearing
Compressive strength 30-35 kg/cm2 90-100 kg/cm2 Higher load-bearing
Absorption 15-25% 10-14% Less dampness
Dimensional stability Very low tolerance High tolerance Saving in mortar up to 25%
Wastage during transit Up to 10% Less than 2% Saving in cost up to 8%
Plastering Thickness varies on both sides of the wall Even on both sides Saving in plaster up to 15%.

Difference Between Red Clay Bricks And Fly Ash Bricks

Difference Between Red Clay Bricks And Fly Ash Bricks:

1- Fly Ash bricks are cast in moulds hence are always of uniform shape. Clay bricks are handmade causing a slight difference in their shape and size.

2- Clay bricks are more porous than Fly ash bricks.

3- Fly ash bricks are lighter in weight and less costly than Clay bricks.

4- Fly ash bricks are made of waste materials which come from the combustion of coal in thermal power plants. Clay bricks are made of clay which is collected from fertile land or the topsoil. This is the prime reason that makes Fly ash bricks more preferable than Clay bricks.

5- In all aspects fly ash bricks are better than clay bricks. They are environment-friendly because maximum constituent is ash and fly ash bricks has greater strength as compared to red bricks.

Fly Ash Bricks Advantage

 1- Due to perfect size savings in cement mortar for making

 the walls and plastering by 20-40%

 2- Strength of supplied lot is similar.

 3- Plaster of Paris, Putty can be applied directly without a

 backing coat of plaster.

 4- Lower water penetration to Clay Bricks.

 5- High Strength-can is used for load-bearing walls.

 6- Eco-friendly using Fly Ash.

Fly Ash bricks Disadvantage

 1- Bonding is lower due to smooth finish, this can be easily

 corrected by using a cement: sand mortar of 1:4 and proper

 curing. Also, the quality of the sand needs to be checked.

Clay Bricks Advantage

1- clay brick at high temperatures is weakly acidic, alkaline slag erosion resistance to a bit weak, but with Al2O3 content increased and enhanced. Thermal stability than the refractory brick, magnesia brick as well.

 2- After the blast of acceptable quality clay dried vacuum impregnation process phosphoric acid, phosphoric acid impregnated low-temperature firing of secondary products, it can be used for masonry lining blast furnace body portion.

 3- Brick from local materials, cheap, durable, as well as fire protection, thermal insulation, sound insulation, moisture absorption, etc., used in a wide range of engineering works. Waste and scrap refractory bricks can be made of concrete aggregate.

Clay Bricks Disadvantage

 1- Uneven shape

 2- Labour Intensive.

 3- Inefficient Kilns Coal Fired -Pollution

 4- Cutting of agricultural land and hills -Pollution and

 against world food security.

Fly ash brick

Fly ash brick

Fly ash brick (FAB) is a building material, specifically masonry units, containing class C or class F fly ash and water. Compressed at 28 MPa (272 atm) and cured for 24 hours in a 66 °C steam bath, then toughened with an air-entrainment agent, the bricks last for more than 100 freeze-thaw cycles. Owing to the high concentration of calcium oxide in class C fly ash, the brick is described as “self-cementing”. The manufacturing method saves energy, reduces mercury pollution and costs 20% less than traditional clay brick manufacturing.       

History:-

Coal dust has historically been collected as a waste product from homes and industry. During the 19th century, coal ash was taken by ‘scavengers’ and delivered to local brickworks, where the ash would be mixed with clay. The income from the sale of ash would normally pay for the collection of waste. 

Clay is typically entrapped during the formation of coal. When coal is burnt, the incombustible clay particles are left behind as ash. Ingrate boilers, and incombustible ash agglomerates as cinders through prolonged residential time. Nowadays, pulverised coal technology is preferred due to its improved energy efficiency. In this case, the ground clay escapes along with flue gases, settling as ash in bag filters or electrostatic precipitators (ESPs). This gives rise to the name ‘fly ash’.

The raw materials:-

Fenton Creek. Presumably, this was a navigable channel in the days when the brickworks was serviced by barges bringing fly ash from London and returning with loads of bricks.

The raw materials for Fly Ash Bricks are:

  Material Mass  

  Fly Ash = 60%  

  Sand / Stone dust =30 %  

  Ordinary Portland Cement/(Lime+Gypsum)= 10%  

  Total formula of material = 100%  

 The strength of fly ash brick manufactured with the above compositions ranges between 7.5 MPa and 10 MPa. Fly ash bricks are lighter and stronger than clay bricks.

The main ingredients include fly ash, water, quicklime or lime sludge, cement, aluminium powder and gypsum. Autoclaving increases the hardness of the block by promoting quick curing of the cement. Gypsum acts as a long term strength gainer. The chemical reaction due to the aluminium paste provides AAC with its distinct porous structure, lightness, and insulating properties. The aforementioned properties set it apart from other lightweight concrete materials. The finished product is a lighter block, less than 40% the weight of conventional Bricks while providing similar strengths. The specific gravity stays around 0.6 to 0.65. Using these blocks in buildings reduces the dead load, allowing one to save around 30 to 35% of structural steel, and concrete.

Commercial processes fall into two categories; the lime route, and the cement (OPC) route where the latter is used as a source of lime. In the lime route, the composition is fly ash (50%), slaked lime (30%), and anhydrous gypsum (20%), to which 3 to 4 times of stone dust, sand or any inert filler material can be added. In the cement route, the composition is fly ash(76%), OPC (20%), and anhydrite (4%), to which 3 to 4 times filler material can be added.

The following properties of fly ash affect the strength and look of fly ash bricks.

1. Loss of Ignition (LOI): fly ash loses weight when it burns at about 1000 °C due to the presence of carbon and water. The weight loss that happens due to carbon combustion and moisture evaporation is called “Loss on Ignition(LOI)”. This is expressed as a percentage. The lower the loss of Ignition, the better the will be fly ash. As per BIS, it should not be more than 5%.

2. Fineness: fine fly ash has more surface area available to react with lime. This increases pozzolanic activity, which contributes to the strength of fly ash bricks. As per BIS, it should not be more than 320 m2/kg.

3. Calcium (CaO) content: the pozzolanic reactivity of fly ash is more in high calcium fly ash. The greater the pozzolanic activity leads to higher the strength of fly ash brick. As per ASTM C618, fly ash is classified into two types: Class C contains more than 10% lime and Class F fly ash contains less than 10% lime.

Based on boiler operations, fly ash can be additionally classified as LT (low temperature) and HT (high temperature). LT fly ash containing amorphous phases is generated where boiler temperature is not more than 800 °C, whereas HT fly ash containing glassy reactive phases is generated at more than 1000 °C in super thermal plants. LT fly ash reacts well with lime whereas HT fly ash reacts well with OPC.

Advantages

1. It reduces the dead load on structures due to lightweight (2.6 kg, dimension: 230 mm X 110 mm X 70 mm

2. the Same number of bricks will cover more area than clay bricks

3. High fire Insulation

4. Due to high strength, practically no breakage during transport and use.

5. Due to uniform size of bricks mortar required for joints and plaster reduces almost by 50%

6. Due to lower water penetration seepage of water through bricks is considerably reduced.

7. Gypsum Plaster can be directly applied on these bricks without a backing coat of Lime Plaster .

8. These bricks do not require soaking in water for 24 hours. Sprinkling of water before use is enough.

Disadvantages.

1. Mechanical strength is low, but this can be rectified by adding marble waste or mortar between blocks.

2. Limitation of size. Only modular size can be produced. Large size will have more breakages.

3. It is only good for the places like subtropical area or area where climate is warm because it doesn’t absorb heat. But during cold it is not helpful.

Referencs.

Edwin Chadwick (1842). Report to Her Majesty’s Principal Secretary of State for the Home Department, from the Poor Law Commissioners, on an Inquiry into the Sanitary Condition of the Labouring Population of Great Britain. Clowes for HMSO. p. 53.

1. Fly ash for Sustainable Development authored by Dr N Bhanumathidas and N Kalidas; Ark Communications 2002

3. Fly ash for Sustainable Development authored by Dr N Bhanumathidas and N Kalidas; published by Ark Communication 2002

Advantages and Disadvantages of Hoffmann kiln

Advantages and Disadvantages of Hoffmann kiln

Hoffmann kilns is the most commonly used kiln in the production of bricks and some other ceramic products. It is patented by German Friedrich Hoffmann for brick making in the year 1858.

Hoffmann kiln is v…

Uses of Brick

Brick plays a very important role in the field of civil engineering construction. Bricks are used as an alternative to stones for construction purposes. Here some main uses of construction brick are given…

Charactristicks of Brick

It is always desirable to use the best quality brick in construction. Therefore, the Characteristics of a good brick must be investigated. Generally, good bricks possesses the following properties-

  • BricK…

lime pitting of brick

If calcium carbonate is present in brick raw material, quicklime will be produced in the kiln. These quick lime, with the help of water, will form hydrated lime and the process expands. Sufficiently large lime particles located near the surface will pop off a piece of brick which will generally create a circular pit. The process is known as the lime pitting of bricks.

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Brick test details – Quality construction work

List of Brick Tests

  • Absorption test
  • Compressive Strength Test (Crushing Strength Test)
  • Efflorescence Test (Presence of Soluble Salts)
  • Hardness Test
  • Impact Test
  • Dimension Tolerance Test
  • Shape and Size
  • Colour Test
  • Soundness Test
  • Structure Test

Fly ash brick

Fly ash brick (FAB) is a building material, specifically masonry units, containing class C or class F fly ash and water. Compressed at 28 MPa (272 atm) and cured for 24 hours in a 66 °C steam bath, then toughened with an air-entrainment agent, the bricks last for more than 100 freeze-thaw cycles. Owing to the high concentration of calcium oxide in class C fly ash, the brick is described as “self-cementing”. The manufacturing method saves energy, reduces mercury pollution and costs 20% less than traditional clay brick manufacturing.

Classification of Bricks Based on Region

Classification of Bricks Based on Region

Based on the region bricks are of the following kinds:

1.   Cream City Bricks: These bricks are from Milwaukee, Wisconsin. 

2.   London Stock: These bricks are used in London.

3.   Dutch: These are from the Netherlands.

4.   Nanak Shahi Bricks: These are from India. 

5.   Roman: These are used in Roman constructions, 

6.   Staffordshire Blue Brick: These are from England.

Classification of Bricks Based on Shape

Classification of Bricks Based on Shape

Based on shape bricks are of the following kinds:

1.   Bullnose Brick: These bricks are moulded into round angles. They are used for rounded quoin.

2.   Airbricks: These bricks contain holes to circulate air. They are used on suspended floors and cavity walls.

3.   Channel Bricks: They are moulded into the shape of a gutter or channel. They are used in drains. 

4.   Coping Bricks: They can be half-round, chamfered, Saddleback, angled varied according to the thickness of the wall.

5.   Cow Nose Bricks: Bricks have double bullnose known as Cow Nose Bricks.

6.   Capping Bricks: These bricks are used to cap the tops of parapets or freestanding walls. 

7.   Brick Veneers: These bricks are thin and used for cladding.

8.   Curved Sector Bricks: These are curved. They are used in arcs, pavements, etc.

9.   Hollow Bricks: These bricks are around one-third of the weight of normal bricks. They are also called cellular or cavity bricks. Their thickness is from 20-25mm. These bricks pave the way for quicker construction as they can be laid quickly compared to normal bricks. They are used in partitioning. 

10.                  Paving Bricks: These bricks contain a good amount of iron. Iron vitrifies bricks at low temperatures. They are used in garden park floors, and pavements. These bricks withstand the abrasive action of traffic thus making the floor less slippery. 

11.                  Perforated Bricks: These bricks contain cylindrical holes. They are very light in weight. Their preparation method is also easy. They consume less clay than the other bricks. They can be of different shapes like round, square, or rectangular. They are used in the construction of the panels for lightweight, structures, and multistoried frame structures. 

12.                  Purpose Made Bricks: For specific purposes, these bricks are made. Splay and can’t bricks are made for doors and window jambs. Engineering bricks are made for civil engineering constructions such as sewers, manholes, and retaining walls. Fire bricks are made for chimneys and fireworks. Ornamental bricks are made to use for cornices and corbels. Arch bricks are used in arcs.

Classification of Bricks Based on Their Using

Classification of Bricks Based on Their Using

There are many uses of bricks Based on the purpose of their use bricks are of the following kinds:

1.   Common Bricks: These bricks are the most common bricks used. They don’t have any special features or requirements. They have low resistance, low quality, and low compressive strength. They are usually used on the interior walls.

2.   Engineering Bricks: These bricks are known for many reasons. They have high compressive strength and low absorption capacity. They are very strong and dense. They have the good load-bearing capacity, damp proof, and chemical resistance properties. They have a uniform red colour. They are classified as Class A, Class B, and Class C. Class A is the strongest but Class B is the most used. They are used for mainly civil engineering works like sewers, manholes, groundworks, retaining walls, damp proof courses, etc.

Classification of Bricks Based on Shape

Classification of Bricks Based on Weather-resisting Capability

Classification of Bricks Based on Weather-resisting Capability

Based on weather-resisting capability bricks are of the following kinds:

1.   Severe Weather Grade: These types of bricks are used in countries which are covered in snow most of the time of year. These bricks are resistant to any kind of freeze-thaw actions.

2.   Moderate Weather Grade: These types of bricks are used in tropical countries. They can withstand any high temperature. 

3.   No Weather Grade: These bricks do not have any weather resisting capabilities and are used on the inside walls.

Classification of Bricks Based on Using Location

Classification of Bricks Based on Using Location

Based on using location bricks are of the following kinds:

1.   Facing Brick: The façade material of any building is known as facing brick. Facings bricks are standard in size, are stronger than other bricks and also have better durability. The colour is red or brown shades to provide a more aesthetic look to the building. There are many types of facing bricks which use different techniques and technology. Facing bricks should be weather resistant as they are most generally used on the exterior wall of buildings. 

2.   Backing Brick: These types of brick don’t have any special features. They are just used behind the facing bricks to provide support.