Lecture10_cement

Lecture10_cement - Introduction to PCC and Portland Cement...

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CE Materials, Portland Cement, Page 1 Introduction to PCC and Portland Cement Introduction to Concrete ± Composite material ± Neither strong nor tough as steel ± Excellent resistance to water Forms any shape/size of structural elemen ± Forms any shape/size of structural element ± Cheap and readily available ± Good energy and resources conservation ± The world uses 1 ton/person/year Portland Cement Concrete (PCC) cement + aggregate + water + admixtures
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CE Materials, Portland Cement, Page 2 ± Cement: finely pulverized material ± Water: hydrates cement ± Aggregate: granular material Concrete Ingredients ± Coarse aggregate (>#4) ± Fine aggregate (<#4) ± Admixtures ± Chemical additives to improve specific properties/performance ± Waste/ Recyclable Materials Quality Of Concrete ± Aggregate ± 60-75% by volume of PCC ± Adequate strength and durability ± Quality of the paste ± Cement ± Water ± Entrapped/entrained air ± Amount of water (w/c ratio) ± Fixed materials and curing Portland Cement
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CE Materials, Portland Cement, Page 3 Portland Cement ± Hydraulic cement composed primarily of calcium silicate (75 – 80%) ± Develops adhesive and cohesive properties that makes it capable of bonding with that makes it capable of bonding with mineral fragments ± Has setting and hardening properties upon reaction with water Raw Materials ± Calcium sources (CaO) ± Limestone, chalk, seashells ± Contain impurities ± Clay and dolomite – CaCO 3 •MgCO 3 ± Silica sources (SiO 2 ) ± Clays, blast furnace slag ± Also may contain Al 2 O 3 , Fe 2 O 3 , MgO ± May add alumina if necessary (Al 2 O 3 ) ± bauxite Manufacturing Process 1. Crushing raw material ± Dry process - blending and grinding raw materials ± Wet process - final grinding in a slurry process Wet process final grinding in a slurry process (15% more energy) 2. Blending of raw materials by grinding
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CE Materials, Portland Cement, Page 4 Manufacturing Process (cont.) 3. Burning ± Blended materials passed through a rotary kiln ± 1316- 1482°C ± 18-45 m long & 1.8-4.5 m dia. ± Materials melt and form glassy beads (clinker, 5-25mm diameter) 4. Pulverization ± Clinker is cooled, gypsum is added, and mix is pulverized into a fine powder Primary Crusher Limestone Quar y Clay Secondary Crusher Vibrating Screen Individual material silos Material Proportioning Over size materials Water Injection Mix and Blend Slur y Storage Bins Wet Process Oversize materials Dry Process Raw Material Input feed stock Grinding mil Grinding mil Mixing and Blending Silo Air Separator Storage Feed Stock Fines Feed Stock Kiln ~ 1400C (2500F) Coal, gas, or oil fuel Oversize return line Grinding Mil Clinker Cooler Clinker Silo Gypsum Silo Bulk Storage Air Separator Fines Bulk Shipping or Packing Plant Proportioning of Clinker Gypsum and Chemical Composition (Major Components) ± Tricalcium Silicate, C 3 S (45-60%) ± 3CaO SiO 2 ± Dicalcium Silicate, C 2 S (15-30%) ± 2CaO SiO 2 ± Tricalcium Aluminate, C 3 A (6-12%) ± 3CaO Al 2 O 3 ± Tetracalcium Aluminoferrite, C 4 AF (6-8%) ± 4CaO Al 2 O 3 Fe 2 O 3
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This note was uploaded on 06/22/2009 for the course CM 3400 taught by Professor Hassan during the Spring '09 term at LSU.

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Lecture10_cement - Introduction to PCC and Portland Cement...

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