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Unit I.ppt
- 1. UNIT I
- 2. CEMENT • History of cement • Indian Cement Industry • Chemical Composition & functions • Manufacturing Process • Chemical requirements • Grade of cement • Properties of cement • Uses of cement
- 3. HISTORY • As Old as History of Engineering construction • Egyptians used by burning Gypsum • Early Greeks and Romans used by burning Limestones
- 4. Oldest Kilns
- 7. NATURAL CEMENT • Obtained by Burning and Crushing the Stones • Brown in Color • Best Variety is known as Roman Cement • Not strong as Artificial Cement
- 8. ARTIFICIAL CEMENT • Obtained by Burning mixture of Calcareous and Argillaceous materials • Burned at high temperature • Clinker – Mixture of ingredients should be intimate – Should be in Correct proportion …continued
- 9. ARTIFICIAL CEMENT • Cement – Small Quantity of Gypsum added to Clinker – Pulverized into very fine Powder • Invention – Invented by Joseph Aspdin of Leeds in England in 1824 – Named as Portland Cement
- 10. PORTLAND CEMENT
- 11. Indian Cement Industry • Indian Portland Cement manufactured first in 1904 • South India Industrial Ltd • Second Largest Cement Producer
- 12. Indian Cement Industry • Highlights – Energy Consumption Higher – Manpower productivity low – Uses new technologies like vertical roller mill, Roll presses, High Efficiency seperators – Per capita Consumption – 570 N – Better Packaging material, Bulk Containers deserve immediate attention
- 13. Manufacture Of Ordinary Cement • Chemical composition – Argillaceous Clay Predominates – Calcareous Calcium Carbonate Predominates • Harmful constituents of cement – Affects the quality of cement – Alkali Oxides K2O and Na2O – Magnesium Oxide Mgo
- 15. Chemical Analysis Ingredient Percentage Lime (Cao) 62% Silica (Sio2) 22% Alumina(Al2O3) 5% Calcium Sulphate (Caso4) 4% Iron Oxide(Fe2O3) 3% Magnesia (Mgo) 2% Sulphur (S) 1% Alkalies 1%
- 16. Functions of Cement • Lime – If Lime excess the cement unsound and expand and disintegrate – If lime deficiency the strength decreases • Silica – Imparts strength – If excess strength increases at the same time setting time is prolonged …continued
- 17. Functions of Cement • Alumina – Impacts Quick setting property – Act as a Flux – If excess weakens the cement • Calcium sulphate – Increase the initial setting point • Iron Oxide – Imparts Color, hardness and strength …continued
- 18. Functions of Cement • Magnesia – Small amount Imparts Hardness and Color – High amount Cement unsound • Sulphur – Small amount Sound Cement – Excess amount Unsound Cement • Alkalies – Most Alkalies carried by flue gases – Small amount
- 19. Manufacturing Process • Mixing, Burning and Grinding • Mixing – Raw materials-limestone and clay are mixed either in dry or in wet condition – Process known as Dry Process or Wet process
- 20. Mixing – Dry Process • Crushing – Single stage Hammer mill – Crushed Limestone moved to Stacking – Stacker-Reclaimer System used • Storage – Crushed Limestone to Storage hoppers – Fed to the Raw mill – Chemical Analysis done ..continued
- 21. Mixing – Dry Process • Pre-heating – Pumped using as aero pole – 60 degree to 850 degree – Fed to rotary Kiln
- 22. Dry Process Calcareous Material Limestone Argillaceous Material Clay Crushing Crushing Fine Grinding in Ball Mills and Tube Mills Fine Grinding in Ball Mills and Tube Mills Storage Storage Mixing in Correct Proportion Storage Tank For Raw Mix
- 23. Wet Process Calcareous Material Limestone Argillaceous Material Clay Crushing Crushing Storage in Silos Storage in Basins Channel Grinding Mill Formation of Slurry Correcting Basin Storage Tanks
- 25. Burning Process
- 26. Grinding From Storage Tanks Rotary Kiln Gypsum Formation of Clinkers Coolers Grinding of Clinkers in Ball Mills and Tube Mills Storage in Silos Weighting and Packing in Bags Distribution Coal Dust
- 27. Chemical Requirements • Lime Saturation factor – Ratio of Lime to Silica, Alumina and Iron Oxide not > 1.02 and not < 0.66 • Ratio of Alumina to Iron Oxide not < 0.66 • Weight of Insoluble Residue not > 4% • Weight of Magnesia not > 6% • Total loss on ignition not > 5% ..continued
- 28. Chemical Requirements • Oxides subjected to high Clinkering temperature combine to form complex compounds • Based on R.H. Bogue’s work • Called Bogue’s compound
- 29. Chemical Requirements Bogue’s compound Name of the compound Formula Abbreviated Formula Tricalcium Silicate 3 Cao.SiO2 C3S Dicalcium Silicate 2 Cao.SiO2 C2S Tricalcium Aluminate 3 Cao.Al2O3 C3A Tetracalcium aluminoferrite 4 Cao.Al2O3.Fe2O3 C4AF
- 30. Properties of Cement • Strength to the masonry • Excellent binding material • Easily workable • Offers good resistance to the moisture • Possesses good plasticity • Stiffens or Hardens early • Fineness – Affects hydration of strength gain
- 31. Properties of Cement • Soundness – Refers to ability of hardened cement to retains its volume • Setting Time – Affected by Cement Fineness, Chemical content and Admixtures • Strength – Compressive, Tensile and flexural
- 32. Uses of Cement • Building • Transport • Water • Civil • Agriculture • Making joints for Drains and Pipes
- 33. Grade Cement • 53 Grade Cement • Uses – Residential, Commercial, Industrial Complexes – Water Retaining Structures – Prestressed Concrete Units like Bridge- Girders – Precast units like poles, grills, manhole covers, Concrete sleepers, etc
- 34. Grade Cement • OPC 43 Grade Cement • Most Structural Concrete Constructions • Residential & Commercial Complexes • Precast units like Structural Components, Pipes, Poles, Solid & Hollow blocks • Flooring Tiles, Wall Tiles, Dado, etc • Asbestos Cement Products