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Journal of Materials Science

, Volume 18, Issue 10, pp 2939–2946 | Cite as

Creep of Kevlar 49 fibre and a Kevlar 49-cement composite

  • P. L. Walton
  • A. J. Majumdar
Papers

Abstract

The creep strain responses of Kevlar 49 fibres and a Kevlar 49 — cement mortar composite board to sustained stresses have been studied over an extended period in excess of four years at ambient temperature. Single filaments of Kevlar 49, 900 mm in length, were stressed in tension in the range 830 to 1830 MPa. The relationship between creep and elapsed time is represented by the power functionAtn whereA is a function of stress andn is a constant. The creep strain in Kevlar 49 was low compared with other polymers. For example after 1000 days at a stress of 1830 MPa the creep strain was 13% of the initial elastic strain and is predicted by the power function to increase to 14.6% after 4000 days. The Kevlar 49 — mortar composite was subjected to bending stresses in the range 6 to 35 MPa and the creep deflection was monitored. The relationship between creep and time could again be represented by the power functionAtn withA dependent on stress andn constant. The creep was similar to that expected from the matrix alone. The ratio of the creep deflection to the initial deflection after 1000 days at a stress of 6.15 MPa (well below the matrix cracking stress) was 1.31 and at 23.5 MPa (well above the matrix cracking stress) was 1.63.

Keywords

Polymer Ambient Temperature Power Function Extended Period Elastic Strain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    W. N. Findley, J. J. Lai andK. Onaran, “Creep and Relaxation of Non-linear Viscoelastic Materials” (North-Holland Publishing Company, Amsterdam, 1976).Google Scholar
  2. 2.
    A. M. Neville, “Creep of Concrete: Plain, Reinforced and Prestressed” (North-Holland Publishing Company, Amsterdam, 1970).Google Scholar
  3. 3.
    R. N. Swamy andD. D. Theodorakopoulos,Intern. J. Cem. Compos. 1 (1979) 37.Google Scholar
  4. 4.
    H. G. Allen,ibid. 2 (1980) 185.Google Scholar
  5. 5.
    B. A. Proctor, Proceedings of Concrete International, 80, London, 1980 (Construction Press, Lancaster, 1980) p. 69.Google Scholar
  6. 6.
    P. L. Walton andA. J. Majumdar,J. Mater. Sci. 13 (1978) 1083.Google Scholar
  7. 7.
    A. R. Bunsell,ibid. 10 (1975) 1300.Google Scholar
  8. 8.
    R. H. Ericksen,Composites 7 (1976) 189.Google Scholar
  9. 9.
    M. H. Horn, P. G. Riewald andC. H. Zweben, Oceans '77 Conference Record Vol. 1 (IEEE, New York, 1977 and MTS, Washington DC, 1977).Google Scholar
  10. 10.
    C. C. Chiao, R. J. Sherry andN. W. Hetherington,J. Compos. Mater. 11 (1977) 79.Google Scholar
  11. 11.
    J. Aveston, G. A. Cooper andA. Kelley, Conference Proceedings, National Physical Laboratory (IPC, London 1971) Paper 1, p. 15.Google Scholar
  12. 12.
    H. G. Allen,J. Compos. Mater. 5 (1971) 194.Google Scholar
  13. 13.
    V. Laws,J. Mater. Sci. 16 (1981) 1299.Google Scholar
  14. 14.
    Idem, J. Mater. Sci. to be published.Google Scholar
  15. 15.
    L. J. Parrott,Mag. Concr. Res. 25 (1973) 197.Google Scholar
  16. 16.
    F. H. Wittman, Conference Proceedings, Sheffield, April 1976 (Cement and Concrete Association, London, 1976) p. 96.Google Scholar

Copyright information

© Chapman and Hall Ltd. 1983

Authors and Affiliations

  • P. L. Walton
    • 1
  • A. J. Majumdar
    • 1
  1. 1.Department of the Environment Building Research StationBuilding Research EstablishmentGarstonUK

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