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CEMENT AND CONCRETE MATERIALS materials fundamentals + mix design

CEMENT AND CONCRETE MATERIALS materials fundamentals + mix design. Christopher Hall 2009 S131 christopher.hall@ed.ac.uk. CEMENT Materials fundamentals Sources of information Cement manufacture + composition Cement hydration Microstructure Concrete mixes Properties: strength

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CEMENT AND CONCRETE MATERIALS materials fundamentals + mix design

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  1. CEMENT AND CONCRETE MATERIALS materials fundamentals + mix design Christopher Hall 2009 S131 christopher.hall@ed.ac.uk

  2. CEMENT Materials fundamentals • Sources of information • Cement manufacture + composition • Cement hydration • Microstructure • Concrete mixes • Properties: strength permeability durability

  3. Information/texts • Jackson & Dhir: Civil Engineering Materials, 5th edn, 1997 • Mindess, Young & Darwin: Concrete, 2002 • Neville & Brooks: Concrete Technology, 1987 • Neville: Properties of Concrete, 4th edn, 1995 • Bensted & Barnes: Structure and Performance of Cements, 2nd edn, 2001

  4. Information/journals • Cement and Concrete Research • Magazine of Concrete Research • American Concrete Institute Journal ACI Journal • Materials and Structures [RILEM]

  5. Information/websites Virtual Cement & Concrete Testing Laboratory includes Electronic monograph from Bentz at NIST: http://ciks.cbt.nist.gov/vcctl/ See also microstructure images library from Lange at UIUC: https://netfiles.uiuc.edu/dlange/www/CML

  6. Cement Manufacture Raw materials limestone + clay on firing, produces a complex mixture of synthetic minerals, principally calcium silicates and calcium aluminates

  7. Manufacture

  8. CEMENT World production 2001 1.6 billion tons

  9. CEMENT World production 2001 1.6 billion tons Steel production 900 million tons

  10. Various figures are quoted. The energy cost of manufacture is around 3500 kJ/kg cement CEMENT World production 2001 1.6 billion tonnes 2--5 % total CO2 emission Energy intensive manufacture

  11. CEMENT World production 2001 1.6 billion tonnes EU production 2002 194 million tonnes For each tonne cement produced 0.800 tonne CO2 is also produced 0.525 tonne from decalcination of limestone 0.335 tonne from combustion of fuel in the kiln 0.050 tonne from electricity production

  12. CEMENT In EU, cement industry produces 3 per cent of total anthropogenic CO2 Source: Cembureau

  13. CEMENT COMPOSITIONS SiO2 OPC zone CaO Al2O3 Fe2O3

  14. CEMENT COMPOSITION Notation CaO Al2O3 Fe2O3 SiO2

  15. CEMENT COMPOSITION Notation CaO C Al2O3 A Fe2O3 F SiO2 S

  16. CEMENT COMPOSITION Notation CaO C Al2O3 A Fe2O3 F SiO2 S

  17. Clinker microstructure C3S C2S C3A C4AF 150 micron C3S C2S

  18. Clinker microstructure C3S C2S C3A C4AF 150 micron C3S C2S

  19. Clinker microstructure C3S C2S C3A C4AF 150 micron C3S C2S

  20. Clinker microstructure C3S C2S C2A C4AF C3A C4AF

  21. C3A C4AF

  22. Clinker microstructure C3S, C2S, C3A, C4AF 200 micron

  23. Cement grinding Gypsum additions (strictly sulphate) Particle size distribution Images from Lange UIUC http://cee.ce.uiuc.edu/lange/micro

  24. Cement hydration 1 Heat evolution Induction period

  25. Cement hydration 2 Chemical reaction with water All minerals involved 115 micron

  26. Cement hydration 2 Principal reaction which develops strength C3S + water ---> C-S-H

  27. Cement hydration 3 Chemical reaction with water All minerals involved Formation of lime (calcium hydroxide) pH of pore water

  28. Cement hydration 4 Water requirement about 30% by wt cement for complete reaction

  29. Cement hydration 5 Four stages of hydration in a microstructural model of C3S hydration. The degrees of hydration are: top left--0% top right--20%, bottom left--50% bottom right--87% Red=unreacted cement blue=CH yellow=C-S-H black= porosity from Bentz, NIST

  30. Computational materials science Cellular automaton model of cement and concrete D Bentz and E Garboczi NIST

  31. Cement hydration 6 Synchrotron X-ray view

  32. Summary of setting and hardening Workability Development of continuous network of hydrate material Strength development Porosity and permeability Timescale

  33. Strength and strength development

  34. Cement Based Materials Mortars Concrete Manufactured cement based materials Autoclaved aerated concrete

  35. Transport properties Permeability Sorptivity see Hall & Hoff: Water Transport in Brick, Stone and Concrete 2002

  36. PERMEABILITY property Darcy’s law: u = Q/A = -  kp /L k permeability Q volume rate of flow

  37. B A

  38. Types of cements Portland cement Blended or composite cements Portland + other mineral components

  39. BS EN 197-1 Cement Other mineral components are Minerals which react with lime Pozzolans Blastfurnace slag Fly ash Natural pozzolans Inert fillers Crushed limestone

  40. BS EN 197-1 Cement

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