cement - uses, types and manufacturing process.pptx

building material

1. Cement: Cement is the mixture of calcareous, siliceous, argillaceous and other substances. Cement is used as a binding material in mortar, concrete, etc.  Cement is a building material for binding bricks, stones or aggregates.  Used for making mortar or concrete.  Cements- natural and artificial.  Natural cement-burning and crushing of stones and lime.  Artificial cement-burning at high temperature and gypsum is added.

2. Composition  Lime- excess will decrease the strength. Deficiency will make it set quickly.  Silica- higher silica increases the strength but setting time is prolonged.  Alumina- results in quick setting. Excess alumina weakens cement.  Iron oxide- for hardness and strength.  Magnesia- hardness and colour .

3. 13 Types of Cement and their Uses Ordinary Portland Cement (OPC) Portland Pozzolana Cement (PPC) Rapid Hardening Cement Quick setting cement Low Heat Cement Sulfates resisting cement Blast Furnace Slag Cement High Alumina Cement White Cement Colored cement Air Entraining Cement Expansive cement Hydrographic cement

4. Ordinary Portland Cement (OPC) Ordinary Portland cement  is the most widely used type of cement, which is suitable for all general concrete construction. It is the most commonly produced and used type of cement around the world, with annual global production of around 3.8 million cubic meters per year.  This cement is suitable for all kinds of concrete construction.

5. 2. Portland Pozzolana Cement (PPC) Portland pozzolana cement  is prepared by grinding pozzolanic clinker with Portland cement. It is also produced by adding pozzolana with the addition of gypsum or calcium sulfate or by intimately and uniformly blending Portland cement and fine pozzolana . . This cement has a high resistance to various chemical attacks on concrete compared with ordinary portland cement, and thus, it is widely used. It is used in marine structures, sewage works, sewage works, and for laying concrete underwater, such as bridges, piers, dams, and mass concrete works, etc

6. 3. Rapid Hardening Cement Rapid hardening cement attains high strength in the early days; it is used in concrete where formworks are removed at an early stage and are similar to ordinary portland cement (OPC). This cement has increased lime content and contains higher c3s content and finer grinding, which gives higher strength development than OPC at an early stage. The strength of rapid hardening cement at the three days is similar to 7 days strength of OPC with the same water-cement ratio. Thus, the advantage of this cement is that formwork can be removed earlier, which increases the rate of construction and decreases the cost of construction by saving formwork cost. Rapid hardening cement is used in prefabricated concrete construction, road works, etc.

7. 4. Quick setting cement The difference between the quick setting cement and rapid hardening cement is that quick-setting cement sets earlier. At the same time, the rate of gain of strength is similar to Ordinary Portland Cement, while quick hardening cement gains strength quickly. Formworks in both cases can be removed earlier. Quick setting cement is used where works is to be completed in very short period and for concreting in static or running water

8. 5. Low Heat Cement Low heat cement is produced by maintaining the percentage of tricalcium aluminate below 6% by increasing the proportion of C2S. A small quantity of tricalcium aluminate makes the concrete to produce low heat of hydration. Low heat cement suitable for mass concrete construction like gravity dams, as the low heat of hydration, prevents the cracking of concrete due to heat. This cement has increased power against sulphates and is less reactive and initial setting time is greater than OPC.

9. 6. Sulfates Resisting Cement Sulfate resisting cement is used to reduce the risk of sulfate attack on concrete and thus is used in the construction of foundations where the soil has high sulfate content. This cement has reduced the contents of C3A and C4AF. Sulfate resisting cement is used in construction exposed to severe sulfate action by water and soil in places like canals linings, culverts, retaining walls, siphons, etc. 7. Blast Furnace Slag Cement Blast furnace slag cement is obtained by grinding the clinkers with about 60% slag and resembles more or less in properties of Portland cement. It can be used for works where economic considerations are predominant.

10. 8. High Alumina Cement High alumina cement is obtained by melting a mixture of bauxite and lime and grinding with the clinker. It is a rapid hardening cement with initial and final setting time of about 3.5 and 5 hours, respectively. The compressive strength of this cement is very high and more workable than ordinary portland cement and is used in works where concrete is subjected to high temperatures, frost, and acidic action. 9. White Cement It is prepared from raw materials free from Iron oxide and is a type of ordinary portland cement, which is white. It is costlier and is used for architectural purposes such as precast curtain wall and facing panels, terrazzo surface, etc. and for interior and exterior decorative work like external renderings of buildings, facing slabs, floorings, ornamental concrete products, paths of gardens, swimming pools, etc.

11. 10. Colored cement It is produced by mixing 5- 10% mineral pigments with ordinary cement. They are widely used for decorative works on floors. 11. Air Entraining Cement Air entraining cement is produced by adding indigenous air-entraining agents such as resins, glues, sodium salts of sulfates, etc. during the grinding of clinker. This type of cement is especially suited to improve the workability with a smaller water-cement ratio and to improve frost resistance of concrete. The primary  use  of  air - entraining concrete  is for freeze-thaw resistance. The  air  voids provide pressure relief sites during a freeze event, allowing the water inside the  concrete  to freeze without inducing large internal stresses. Another related  use  is for deicer-scaling resistance.

12. 12. Expansive Cement Expansive cement expands slightly with time and does not shrink during and after the time of hardening. This cement is mainly used for grouting anchor bolts and prestressed concrete ducts. 13. Hydrographic cement Hydrographic cement is prepared by mixing water-repelling chemicals and has high workability and strength. It has the property of repelling water and is unaffected during monsoon or rains. Hydrophobic cement is mainly used for the construction of water structures such as dams, water tanks, spillways, water retaining structures, etc.

13. To prepare cement mortar To prepare cement concrete To build fire proof and thermal proof structures To build hydrographic and frost resistant structures To build chemical proof structures As a grout material To construct Cement concrete roads To manufacture precast members For aesthetic concrete constructio Uses of cement

14. 1. To Prepare Cement Mortar Cement mortar is like a paste which is prepared by adding certain quantity of water to cement and sand mixture. Cement in this case is denoted as matrix while sand is termed as adulterant. We know Cement has good binding properties while there are other binding materials are also available, but cement is mostly used because of its high strength and water resisting properties. It is used to create a strong bond between bricks, stones in a masonry. Plastering is done by cement mortar which gives smooth finish to the structure. Cement molds of different shapes can be made using cement mortar. It is also used to seal the joints of brickwork and stone work or cracks. Generally, the cement sand ratio in a mortar is in between 1:2 to 1:6. The ratio of cement and sand mix is decided based on the importance of work.

15. 2. To Prepare Cement Concrete Cement concrete is a major building material in the world which is widely using because of its marvelous structural properties. The ingredients of cement concrete are cement, fine aggregate, coarse aggregate and water respectively. In general, ordinary Portland cement is used to prepare concrete. But for special cases or based on different circumstances many types of cements like rapid hardening cement, high alumina cement etc. are discovered.

16. 3. To Build Fire Proof or Heat Proof Structures To with stand against high temperatures and to prevent fire accidents structures should be built with great fire-resistant materials like cement. High alumina cement is more suitable material to make concrete for the structures in high temperature regions.

17. 4. To Build Hydrographic and Frost Resistant Structures Most of the hydrographic structures in the world are built using concrete with cement as binding material. The structures built in water or in contact with water should be very strong against moisture and they should be water tight. Many types of cements like hydrophobic cement, expanding cement, pozzolana cement, quick setting cement etc. are most suitable for constructing water retaining structures. Quick setting cement is very much useful in the case when there is limited time to construct under water structures. Hydrophobic cement had more resistance against frost actions, so it can be used to build structures in snow regions also.

18. 5. To Build Chemical Proof Structures In chemical industries, different chemicals are stored and they may damage the structure if proper resistance is not there. Acid resistant cement is very much useful in this case. Similarly, for the constructions under marine conditions, sewage carrying structures etc. Sulphate resistant cement is useful.

19. 6. For Grouting Grouting is the process of filling cracks, joints, openings in foundations or any other structural members to improve their strength. In general, ordinary Portland cements is used as grout material to which required amount of water and sand is added. To fill very fine cracks or to fill deep thin cracks micro fine cement is most suitable. Micro fine cement contains very finer particles than the ordinary Portland cement so it can flow into very fine and deep cracks in quick time.

20. 7. To Construct Cement Concrete Roads Cement concrete roads are more famous as high standard roads which are stronger than all other types of roads. They are also called as rigid pavements because of their rigid nature. C.C roads have long life span even without proper maintenance. Load wise also they are much capable than all other types. 8. To Manufacture Precast Members Many precast members are made using cement as binding material. Cement concrete pipes are widely used as drains, pipes under culverts etc. Cement concrete brick masonry is more famous because of the size of block, ease of construction and strength etc. Water tanks and septic tanks are generally constructed by cement concrete rings. Many other things like garden seats, flower pots, dust bins, lam posts etc. are manufactured using cement.

21. 9. For Aesthetic Structures Now a days cement is available in many colors. This is done by adding coloring agent while manufacturing cement but the percentage of coloring agent should be below 10%. Some of the coloring agents are iron oxide which gives red or brown, cobalt which gives blue etc. The colored cement makes the structure beautiful without any painting. Colored cements generally used for floor finishing, stair treads, window sill slabs, external wall surfaces etc..

22. MANUFACTURING OF CEMENT PORTLAND CEMENT

23. Manufacturing Process Of Portland Cement  Step 1 . Mixing Of Raw Materials The major raw materials used in the manufacture of cement are Calcium, Silicon, Iron and Aluminum. These minerals are used in different form as per the availability of the minerals. The Calcareous and Argillaceous Materials used in Manufacturing Process of Portland Cement are shown in the Table in the Next Slide.

24. Manufacturing Processes Of Portland Cement There are 2-Types of Processes that can be used to Manufacture Portland Cement. Which are : 1 Wet Process 2 Dry Process

25. DRY Process • The both calcareous and argillaceous raw materials are firstly crushed in the gyratory crushers to get 2-5cm size pieces separately. The crushed materials are again grinded to get fine particles into ball or tube mill. • Each finely grinded material is stored in hopper after screening. Now these powdered minerals are mixed in required proportion to get dry raw mix which is then stored in silos and kept ready to be sent into rotary kiln. Now the raw materials are mixed in specific proportions so that the average composition of the final product is maintained properly.

26. WET Process • The raw materials are firstly crushed and made into powdered form and stored in silos. The clay is then washed in washing mills to remove adhering organic matters found in clay. • The powdered limestone and water washed clay are sent to flow in the channels and transfer to grinding mills where they are completely mixed and the paste is formed, i.e., known as slurry. • The grinding process can be done in ball or tube mill or even both. Then the slurry is led into collecting basin where composition can be adjusted. The slurry contains around 38-40% water that is stored in storage tanks and kept ready for the rotary kiln.

27.  Step 2. Grinding Of Clinkers • The cooled clinkers are received from the cooling pans and sent into mills. The clinkers are grinded finely into powder in ball mill or tube mill. Powdered gypsum is added around 2-3% as retarding agent during final grinding. The final obtained product is cement that does not settle quickly when comes in contact with water. • After the initial setting time of the cement, the cement becomes stiff and the gypsum retards the dissolution of tri-calcium aluminates by forming tricalcium sulfoaluminate which is insoluble and prevents too early further reactions of setting and hardening. 3CaO.Al2O3 + xCaSO4.7H2O = 3CaO.Al2O3.xCaSO4.7H2O

28.  Step 3 . Storage and Packaging • The grinded cement is stored in silos, from which it is marketed either in container load or 50kg bags.

29.  FIELD TESTING  LABORATORY TESTING METHODS OF TESTING

30. Open the bag and take a good look at the cement, then it should not contain any visible lumps.  Colour of cement should be greenish grey.  Should get cool feeling when thrusted .  When we touch the cement, it should give a smooth &not a gritty feeling.  When we throw the cement on a bucket full of water before it sinks the particles should flow.  When we make a stiff paste of cement & cut it with sharp edges & kept on a glass plate under water there wont be any disturbance to the shape& should get strength after 24hours. FIELD TESTING

31.  Fineness test  Standard consistency test  Setting time test  Strength test  Soundness test  Heat of hydration test  Chemical composition test LABORATORY TESTS