The document provides information about coarse aggregate, cement manufacturing, and presents a report. It defines coarse aggregate as irregular granular materials like sand and gravel used to make concrete. The selection of aggregates is important. Cement is a binding agent made from limestone, sand, clay, and other materials. It is produced by heating ingredients in cement plants to form a rock-hard substance that is ground into a fine powder. The cement manufacturing process involves quarrying materials, crushing, grinding, heating in a kiln to over 2700 degrees Fahrenheit, and cooling and grinding the resulting clinker.

1. PRESENTATION
REPORT
NAME– KARANBHATT
CLASS– CIVILB
ROLL NO. - 10521191

2. COARSE AGGREGATE
Coarse aggregates refer to irregular and granular materials such as
sand, gravel, or crushed stone, and are used for making concrete. In
most cases, Coarse is naturally occurring and can be obtained by
blasting quarries or crushing them by hand or crushers. It is
imperative to wash them before using them for producing concrete.
Their angularity and strength affect the concrete in numerous ways.
Needless to say, the selection of these aggregates is a very important
process.
Materials that are large enough to be retained on the 4.7mm sieve
size usually constitute coarse aggregates and can reach a maximum size
of 63mm.

3. MANUFACTURING PROCESS
Gravels constitute the majority of coarse aggregate used in concrete
with crushed stone making up most of the remainder. Natural gravel
and sand are usually dug or dredged from a pit, river, lake, or seabed.
Crushed aggregate is produced by crushing quarry rock, boulders,
cobbles, or large-size gravel. Recycled concrete is a viable source of
aggregate and has been satisfactorily used in granular subbases, soil-
cement, and in new concrete.
After harvesting, aggregate is processed: crushed, screened, and
washed to obtain proper cleanliness and gradation. If necessary, a
benefaction process such as jigging or heavy media separation can be
used to upgrade the quality. Once processeds, the aggregates are
handled and stored to minimize segregation and degradation and
prevent contamination.

4. FINE AGGREGATE

6. CEMENT
Cement, one of the most important building materials, is a binding
agent that sets and hardens to adhere to building units such as
stones, bricks, tiles, etc. Cement generally refers to a very fine
powdery substance chiefly made up of limestone (calcium), sand or
clay (silicon), bauxite (aluminum) and iron ore, and may include shells,
chalk, marl, shale, clay, blast furnace slag, slate. The raw ingredients
are processed in cement manufacturing plants and heated to form a
rock-hard substance, which is then ground into a fine powder to be
sold. Cement mixed with water causes a chemical reaction and forms a
paste that sets and hardens to bind individual structures of building
materials.
Cement is an integral part of the urban infrastructure. It is used to
make concrete as well as mortar, and to secure the infrastructure by
binding the building blocks. Concrete is made of cement, water, sand,
and gravel mixed in definite proportions, whereas mortar consists of
cement, water, and lime aggregate. These are both used to bind
rocks, stones, bricks, and other building units, fill or seal any gaps,
and to make decorative patterns. Cement mixed with water silicates
and aluminates, making a water repellant hardened mass that is used
for water-proofing.

7. MANUFACTURING PROCESS
Cement is manufactured through a closely controlled chemical combination
of calcium, silicon, aluminum, iron and other ingredients.
Common materials used to manufacture cement include limestone, shells,
and chalk or marl combined with shale, clay, slate, blast furnace slag,
silica sand, and iron ore. These ingredients, when heated at high
temperatures form a rock-like substance that is ground into the fine
powder that we commonly think of as cement.
Cement plant laboratories check each step in the manufacture of
Portland cement by frequent chemical and physical tests. The labs also
analyze and test the finished product to ensure that it complies with all
industry specifications.
The most common way to manufacture Portland cement is through a dry
method. The first step is to quarry the principal raw materials, mainly
limestone, clay, and other materials. After quarrying the rock is crushed.
This involves several stages. The first crushing reduces the rock to a
maximum size of about 6 inches. The rock then goes to secondary
crushers or hammer mills for reduction to about 3 inches or smaller.
The crushed rock is combined with other ingredients such as iron ore or
fly ash and ground, mixed, and fed to a cement kiln.

8. The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge
cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as
12 feet in diameter—large enough to accommodate an automobile and longer in many
instances than the height of a 40-story building. The large kilns are mounted with the
axis inclined slightly from the horizontal.
The finely ground raw material or the slurry is fed into the higher end. At the lower
end is a roaring blast of flame, produced by precisely controlled burning of powdered
coal, oil, alternative fuels, or gas under forced draft.
As the material moves through the kiln, certain elements are driven off in the form of
gases. The remaining elements unite to form a new substance called clinker. Clinker
comes out of the kiln as grey balls, about the size of marbles.
Clinker is discharged red-hot from the lower end of the kiln and generally is brought
down to handling temperature in various types of coolers. The heated air from the
coolers is returned to the kilns, a process that saves fuel and increases burning efficiency.
After the clinker is cooled, cement plants grind it and mix it with small amounts of
gypsum and limestone. Cement is so fine that 1 pound of cement contains 150 billion
grains. The cement is now ready for transport to ready-mix concrete companies to be
used in a variety of construction projects.
Although the dry process is the most modern and popular way to manufacture cement,
some kilns in the United States use a wet process. The two processes are essentially
alike except in the wet process, the raw materials are ground with water before being
fed into the kiln.

10. THANK YOU