Portland Cement- The hydraulic Binder.pptx

A cement hydraulic binder refers to a type of cement that sets and hardens by chemical reactions with water and is capable of doing so even underwater. The most common type of hydraulic binder is Portland cement, which is the primary component in concrete and mortar.

1. CEMENT- a hydraulic binder Md. Tahmidul Islam Mongla Cement Factory Mongla , Bagerhat Bangladesh Email: [email protected] [email protected]

2. Portland cement may be defined as in the British standard as a product obtained by intimately mixing together calcareous and argillaceous or other silica, alumina and iron oxide bearing materials, burning them at a clinkering temperature, and grinding the resulting clinker. Calcareous materials : Lime Stone (65-80% CaCO 3 ), Marly limestone, Coral limestone, Chalk, Shale, Calcite Argillaceous materials : Silica, Alumina and Iron Oxide. Clay, Marly clay, Shale, Blast Furnace Slag, sand etc. Gypsum CaSO 4 .2H 2 O or Plaster of Paris CaSO 4 .½H 2 O acts as retarder to prevent quick setting. After initial setting gypsum retards the dissolution of tricalcium aluminate by forming tricalcium sulphoaluminate (3CaO.Al 2 O 3 .xCaSO 4 .7H 2 O). mixed with 2-5 % gypsum (CaSO 4 ,2H 2 O). Portland Cement

3. History of Cement In 1824, Joseph Aspdin , a British stone mason, obtained a patent for Portland cement. The inventor heated a mixture of finely ground limestone and clay in his kitchen and ground the mixture into a powder creating a hydraulic cement. Aspdin named the product Portland cement because it resembled a stone quarried on the Isle of Portland, England . In 1756 to rebuilt Eddystone Lighthouse, John Smeaton conducted a number of experiments that led to the discovery that cement made from limestone containing a considerable proportion of clay would harden under water. Dates back to the thousands of years, the Egyptians used natural cement made by combining limestone and gypsum for the construction of pyramids Romans used a combination of slaked lime with volcanic ash found near Pozzuoli village near Mount Vesuvius, Italy. Best know surviving example is the Pantheon in Rome

4. PORTLAND CEMENT MANUFACTURING PROCESS 1 ton of Portland cement required approx. 1,6 tons of raw materials

5. CEMENT PRODUCTION –A SNAPSHOT

6. MAIN CHEMICAL COMPOUND OF PORTLAND CEMENT Name of compound Chemical composition Usual abbreviation Reaction Tricalcium silicate Dicalcium silicate Tricalcium aluminate Tetracalcium aluminoferrite 3CaO.SiO 2 2CaO.SiO 2 3CaO.A2O3 4CaO.Al2O3.Fe2O3 C 3 S C 2 S C 3 A C 4 AF Quick reaction Slow reaction Very quick reaction Not very important

7. CHEMISTRY OF Portland Cement C - CaO , S - SiO 2 , A - Al 2 O 3 , F - Fe 2 O 3 C 3 S, C 2 S, C 3 A and C 4 AF are the main crystalline phases of Portland cement Mineralogical composition Composition Abbreviation Approx Percentage Function Tricalcium silicate 3CaO.SiO 2 C 3 S 45-65% Rapid Contribution to strength Dicalcium silicate 2CaO. SiO 2 C 2 S 12-30% Slow Contribution to strength Tricalcium aluminate 3CaO.Al 2 O 3 C 3 A 6-12% Rapid Contribution to strength Tetracalcium aluminoferrite 4CaO. Al 2 O 3 .Fe 2 O 3 C 4 AF 6-15% Very Slow Contribution to strength

8. HYDRATION OF Portland Cement C3S is responsible for early strength of concrete • C2S is responsible for later strength of concrete • C-S-H gel makes up 50-60% of volume of solids in a completely hydrated cement paste. It determines the good properties of concrete • Ca(OH)2 is soluble in water and gets leached out making concrete porous, particularly in hydraulic structures In cement nomenclature C 3 S + Water C-S-H + 3CH + Heat C 2 S + Water C-S-H + CH + Heat 2Ca 3 SiO 5 + 6 H 2 O Ca 3 Si 2 O 7 . 3H 2 O + 3Ca(OH) 2 + 125 cal/gC 3 S 2Ca 2 SiO 4 + 4 H 2 O Ca 3 Si 2 O 7 . 3H 2 O + Ca(OH) 2 + 62 cal/gC 2 S C 3 S and C 2 S are the two major component that contribute to the ultimate strength as they hydrate. The majority of the hydration of C 3 S reaction has taken place within 28 days and is to a large degree effectively complete after one year. But in case of C 2 S hydration reaction occurs after 28 days and significant hydration ensues beyond one year.

9. A TYPICAL CLINKER COMPOSITION Composition Percentage Calcium oxide ( CaO ) 63-66% Silicon di oxide (SiO 2 ) 19-22% Aluminum oxide (Al 2 O 3 ) 4-6% Ferric oxide (Fe 2 O 3 ) 2-4% Magnesium oxide ( MgO ) 5% Max Sulphuric Anhydride (SO 3 ) 1% Max Sodium oxide (Na 2 O) 0.5% Max Potassium oxide (K 2 O) 0.5% Max Free lime (Free CaO ) 1% Max Loss on ignition 0.5% Max Insoluble residue 0.5% Max Chloride 0.1% Max Tricalcium silicate (C 3 S) 45- 65% Dicalcium silicate (C 2 S) 12-25% Tricalcium aluminate (C 3 A) 6-12% Tetra calcium aluminoferrite (C4AF) 6-15%

10. CEMENT STANDARD ASTM (American Society for Testing and Materials) EN ( Europeen de Normalisation ) European standard EN 197-1: 2000 is adopted as a BDS Standard Bangladesh Standard BDS:EN 197-1: 2003

11. CEM I Portland cement CEM II Portland Composite cements Portland slag cement Portland silica fume cement Portland fly ash cement Portland limestone cement Portland composite cement CEM III Blast furnace cement CEM IV Pozzolanic cement CEM V Composite cement CEMENT CLASSIFICATION As per Bangladesh Standard (BSTI)/European Standard (EN Standard ) EN 197-1 defines and gives the specification of 27 distinct common cement products and their constituents

12. Nomenclature Others main components of composite cements S – Blast furnace slag D - Silica fume P – Natural pozzolana Q - Natural Calcined pozzalona V – Siliceous fly ash W – Calcarious fly ash L - Limestone T – Burnt shale M - Composite (two or more of the above)

13. MECHANICAL and PHYSICAL REQUIREMENTS 1 MPa = 1 N/mm 2 = 145 PSI As per BDS EN Standard MPa = Mega Pascal N/mm 2 = Newton/millimeter 2 PSI = Pound per square inch Strength class Compressive Strength MPa Initial setting time minute Soundness (expansion) mm Early Strength Standard strength 2 days 7 days 28 days 32.5 N -- ≥ 16.0 ≥ 32.5 ≤ 52.5 ≤ 75 ≤ 10 32.5 R ≥ 10.0 -- 42.5 N ≥ 10.0 -- ≥ 42.5 ≤ 62.5 ≤ 60 42.5 R ≥ 20.0 -- 52.5 N ≥ 20.0 -- ≥ 52.5 -- ≤ 45 52.5 R ≥ 30.0 --

14. CHEMICAL REQUIREMENTS Property Cement type Strength class Requirements Loss on ignition CEM I CEM III All ≤ 5.0% Insoluble residue CEM I CEMIII All ≤ 5.0% Sulfate content (as SO3) CEM I CEM II CEM IV CEM V 32.5 N 32.5 R 52.5 N ≤ 3.5% 42.5 R 52.5 N 52.5 R ≤ 4.0% CEM III All Chloride content All All ≤ 0.10% Pozzolanicity CEM IV All Satisfies the test As per BDS EN Standard

15. ELEPHANT BRAND CEMENT PORTLAND COMPOSITE CEMENT BDS:EN 197.2000:CEM II/B-M (SVL) 42.5 N ELEPHANT BRAND PORTLAND COMPOSITE CEMENT SPECIFICATION SL. NO PARAMETERS BDS:EN REQUIREMENT ELEPHANT BRAND 01 Strength 2 DAYS 28 DAYS 10 MPa (1450 PSI) Minimum 42.5 MPa (6162 PSI) Minimum 15 MPa Min 45 MPa Min 02 Setting time Initial ≥ 60 Minute 140 -160 Minute 03 Soundness (Expansion) ≤ 10 mm 2 mm 04 Fineness Specific Surface (Blaine) --------- 4000 cm 2 / gm

16. ELEPHANT BRAND CEMENT PORTLAND COMPOSITE CEMENT BDS:EN 197.2000:CEM I, 52.5 N ELEPHANT BRAND PORTLAND CEMENT SPECIFICATION SL. NO PARAMETERS BDS:EN REQUIREMENT ELEPHANT BRAND 01 STRENGTH 2 DAYS 28 DAYS 20 MPa (2900 PSI) Minimum 52.5 MPa (7612 PSI) Minimum 25 MPa Min 55 MPa Min 02 Setting time Initial ≥ 45 Minute 140 -160 Minute 03 Soundness (Expansion) ≤ 10 mm 2 mm 04 Fineness Specific Surface (Blaine) --------- 3500 cm 2 /gm

17. Harmful Ingredients Permissible limit Harmful effects Affected Structure Chloride ≤ 0.1% Corrosion of reinforcement Alkali (Na2O+ K2O) ≤ 0.6% Exceeds 1 per cent, it leads to the failure of concrete (ASR ) MgO ≤ 5% Cracks mortar or concrete (Expansion) Harmful agents in PORTLAND cement