Booosting 20 jaar vooruit! jubileum oktober 2008 sybrandvd_zwaag

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Booosting 20 jaar vooruit! jubileum oktober 2008 sybrandvd_zwaag

  1. 1. Self Healing : an alternative strategy to make materials perform better July 14, 2011 Sybrand van der Zwaag Faculty of Aerospace Engineering TU Delft Booosting 2008 Rotterdam
  2. 2. Material development over 120 centuries July 14, 2011 After M.F. Ashby
  3. 3. General characteristics of man-made (structural) materials <ul><li>All material processing chains geared towards putting the atoms/molecules at the right place and to make them stay there. </li></ul><ul><li>We improve properties by design principles aimed at avoiding initial (production) damage and/or damage formation during use. </li></ul><ul><li>i.e. we work with DAMAGE PREVENTION only </li></ul>July 14, 2011
  4. 4. lessons from nature ? July 14, 2011 <ul><li>Time dependent degradation </li></ul><ul><li>Cracking </li></ul><ul><li>Ingress agressieve substances </li></ul>Time Performance
  5. 5. More lessons from nature July 14, 2011
  6. 6. July 14, 2011 Assuring a dynamic equilibrium in bone 50 µm Cells to remove material Cells to create material Cells to sense the stress- state
  7. 7. July 14, 2011 Cell activity during remodelling control parameter: P = cell activity OC OB OC > OB Bone mass  P  OB > OC Bone mass  P  set point
  8. 8. The 3 key ingredients of self healing materials <ul><li>most structural units are there to perform the desired mechanical function </li></ul><ul><li>some structural units are mobile to perform self healing at damaged sites </li></ul><ul><li>some structural units are capable of sensing the damage </li></ul>July 14, 2011
  9. 9. Self Healing ambitions (single event) July 14, 2011 Time Performance original improvement SH coating
  10. 10. Self healing ambitions (multiple healing) July 14, 2011 Time Performance original improvement SH coating
  11. 11. Self healing ambition : massive and small scale damage July 14, 2011 Time Performance original improvement SH coating
  12. 12. Self Healing behaviour <ul><li>An ideal self healing material : </li></ul><ul><li>Repairs the damage for 100 % </li></ul><ul><li>Repairs itself an infinite number or times </li></ul><ul><li>The repair is autonomous </li></ul><ul><li>The material has better properties than the classical material it replaces </li></ul><ul><li>Is cheap </li></ul><ul><li>Is used by architects </li></ul>July 14, 2011 <ul><li>A minimal self healing material </li></ul><ul><li>Repairs the damage by 5% </li></ul><ul><li>Repairs itself only once </li></ul><ul><li>Needs an external stimulus </li></ul><ul><li>Has poorer properties than the classical material it replaces </li></ul><ul><li>Is expensive </li></ul><ul><li>Is used by aerospace engineers </li></ul>
  13. 13. Drivers for self healing materials <ul><li>High repair costs (e.g. subsurface structures) </li></ul><ul><li>High reliability (e.g. aircraft, installations) </li></ul><ul><li>Surface quality (e.g. painst and coatings) </li></ul><ul><li>High degree of irritation when repairs take place (e.g. road repairs) </li></ul>July 14, 2011
  14. 14. Self healing in building materials July 14, 2011 Victor Li (2005)
  15. 15. self-healing mechanisms in concrete <ul><li>Can occur in both flow and non-flow through cracks </li></ul><ul><li>Requires ample supply of carbonates and calcium ions (more common in flow through cracks) </li></ul><ul><li>Interaction of water and concrete achieve passive self healing </li></ul>July 14, 2011 Air = CO 2 CO 2 H 2 CO 3 CO 3 2- CO 3 2- + Ca 2+ Concrete Crack Ca 2+ Water CaCO 3 C. Edvardsen (1999) Concrete Water Crack CO 3 2- + Ca 2+ CaCO 3
  16. 16. Metal-like Behavior of Engineered Cementitious Compound July 14, 2011  cu ~ 4% Victor Li, Michigan, USA 0 1 2 3 4 0 1 2 3 4 5 6 Crack Width (  m) S t r e s s Stress (MPa) 0 2 0 4 0 6 0 8 0 1 0 0 C r a c k w i d t h Strain (%) 20 mm Damage
  17. 17. Self-Healed ECC Specimens July 14, 2011 Before Self-Healing After Self-Healing w ~ 60  m  = 1.5% Formation of CaCO 3 3 mm 3 mm
  18. 18. Mihara Bridge in Hokkaido, 2004 July 14, 2011 Cable Stayed Bridge Hokkaido, Japan Completed: Oct., 2004 Open to traffic: April, 2005 Length: 1000 m, span: 340 m Deck area: 20,000 sq. m.; ECC layer thickness: 38 mm Composite ECC-Steel Deck ECC used for stiffening deck & decrease stress in deck steel FRP shear key applied Weight reduction 40% Cost reduction: 50% Expected service life: 100 yrs
  19. 19. Self Healing bridge in Amsterdam July 14, 2011 van Hees, TUD
  20. 20. Bacteria Stimulated Crack Healing in Concrete July 14, 2011 H.M. Jonkers, Microlab, TU Delft
  21. 21. Alkaliphilic Endospore Bacteria July 14, 2011 Endospores
  22. 22. July 14, 2011 Goal: - Self-healing (blocking / plugging) of cracks results in more durable concrete - Use bacteria that produce bio-minerals (e.g. calcite) Methods: - Create right conditions for bacteria to 1. survive concrete environment for long time 2. produce calcite upon water ingression through cracks - Characterize self-healing of cracks: 1. type of material deposited 2. blocking characteristics 3. (regained) mechanical properties
  23. 23. Bacterial formation of CaC03 crystals on concrete fracture surfaces July 14, 2011 Zonder Met bacteri ën CaCO 3 -kristallen Jonkers, TU Delft
  24. 24. July 14, 2011 Preferred concrete properties: 7. Self-healing! Impregnation techniques to image the effect of healing
  25. 25. July 14, 2011 Why self-healing concrete? The Corrosion Society (USA) estimates the annual direct cost of corrosion in construction and other applications to be $276 billion . Longer service life, less maintenance: saves money and the environment
  26. 26. Self healing in coatings July 14, 2011
  27. 27. Polymer coating structure July 14, 2011 topcoat basecoat primer substrate
  28. 28. Maintaining Performance in natural materials July 14, 2011
  29. 29. Human Skin detail July 14, 2011
  30. 30. Self healing via a liquid agent July 14, 2011 “ The Scott White concept”
  31. 31. The Scott White approach July 14, 2011 = epoxy = liquid adhesive capsule = catalyst S.R. White et al, Nature 2002
  32. 32. Just cracked July 14, 2011
  33. 33. 5 seconds later July 14, 2011
  34. 34. 1 minute later July 14, 2011 = crosslinking adhesive
  35. 35. 45 minutes later July 14, 2011 = fully crosslinked adhesive
  36. 36. Self-Healing Epoxy July 14, 2011  = 90.3% 2.5 wt% Grubbs catalyst 5 wt% microcapsules Healing conditions: room temperature, 48 h
  37. 37. Encapsulation approach in a coating <ul><li>PU coating with DCPD capsules/Cat in Wax </li></ul><ul><li>Fraunhofer IFAM; Farbe & Lack, 10, 35-41 (2007) </li></ul>July 14, 2011
  38. 38. <ul><li>www.small-journal.com </li></ul><ul><li>Small 2007, 6 </li></ul><ul><li>(926-943) </li></ul>July 14, 2011
  39. 39. Coating on Micro vascular substrate July 14, 2011 Kathleen S. Toohey, Nancy R. Sottos, Jennifer A. Lewis, Jeffrey S. Moore & Scott R. White Nature Materials 6 , 581 - 585 (2007)
  40. 40. Molecular Approach to Self Healing in coatings July 14, 2011
  41. 41. Molecular processes in reversible networks (Diels –Alder reactions) July 14, 2011 +
  42. 42. Self healing coatings based on hydrogen bonding July 14, 2011
  43. 43. The future is nearer than you may think July 14, 2011
  44. 44. Concluding remarks <ul><li>Self healing behaviour explains the survival of Roman buildings and structures </li></ul><ul><li>Self healing behaviour is a valuable property for modern building materials </li></ul><ul><li>It is a challenge for architects to make full use of the self healing potential of future materials </li></ul>July 14, 2011

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