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Experimental Determination of Concrete Fracture Properties with Modified S-FPZ Model

  • Published : 2006.12.31

Abstract

Modified singular fracture process zone(S-FPZ) model is proposed in this paper to determine a fracture criterion for continuous crack propagation in concrete. The investigated fracture properties of the proposed fracture model are strain energy release rate at a micro-crack tip and the relationship between crack closure stress(CCS) and crack opening displacement(COD) in the FPZ. The proposed model can simulate the actual fracture energy of experimental results fairly well. The results of the experimental data analysis show that specimen geometry and loading condition did not affect the CCS-COD relation. However, the strain energy release rate is a function of not only specimen geometry but also crack extension. The strain energy release rate remained constantly at the minimum value up to the crack extension of 25 mm, and then it increased linearly to the maximum value. The maximum fracture criterion occurred at the peak load for specimens of large size. The fracture criterion remained at the maximum value after the peak load. The variation of the fracture criterion is caused by micro-cracking and micro-crack localization. The fracture criterion of strain energy release rate can simply be the size effect of concrete fracture, and it can be used to quantify the micro-cracking and micro-crack localizing behavior of concrete.

Keywords

References

  1. Landis, E. and Shah, S. P., 'Recovery of microcrack parameter in mortar using quantitative acoustic emission,' Journal of Nondestructive Evaluation, Vol.12, No.4, 1993, pp.213~232
  2. Li, Z., Kulkarni, S. M., and Shah, S. P., 'New test method for obtaining softening response of unnotched concrete specimen under uniaxial tension, 'Experimental Mechanics, Vol.33, No.3, 1993, pp.181~188 https://doi.org/10.1007/BF02322570
  3. Li,Z., 'Microcrack characterization in concrete under uniaxial tension,' Magazine of Concrete Research, Vol.48, No.176, 1996, pp.219~228 https://doi.org/10.1680/macr.1996.48.176.219
  4. Li, F. and Li, Z., 'Acoustic emission monitoring of fracture of fiber reinforced Concrete in tension,' Material Journal, ACI, Vol.97, No.6, 2000, pp.629~636
  5. Krstulovic Opara, N., 'Fracture process zone presence and behavior in mortar specimens,' Material Journal, ACI, Vol.90, No.6, 1993, pp.618~626
  6. Hillerborg, A., Modeer, M., and Petersson, P.-E., 'Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements,' Cement and Concrete Research, Vol.6, No.6, 1976, pp.773~782 https://doi.org/10.1016/0008-8846(76)90007-7
  7. Bazant, Z. P. and Oh, B. H. 'Crack band theory for fracture of concrete. Materials and Structures,' RILEM, Vol.16, 1983, pp.155~177
  8. Jenq, Y. S. and Shah, S. P., 'A two parameter fracture model for concrete,' Journal of Engineering Mechanics, ASCE, Vol.111, No.4, 1985, pp.1227~1241 https://doi.org/10.1061/(ASCE)0733-9399(1985)111:10(1227)
  9. Yon, J.-H., Hawkins, N. M., and Kobayashi, A. S., 'S-FPZ model for concrete SEN specimen,' Fracture mechanics of concrete structure, Elsevier Applied Science, London, England, 1992, pp.208~213
  10. Bazant, Z. P. and Kazemi, M. T., 'Determination of fracture energy, process zone length and brittleness number from size effect, with application to rock and concrete,' International Journal of Fracture, Vol.44, 1990, pp.111~131 https://doi.org/10.1007/BF00047063
  11. Yon, J.-H., 'Resistance Curves of Propagating Cracks for Concrete Three-Point Bend Specimens,' Journal of the Korea Concrete Institute , Vol.13, No.6, 2001, pp.568~574
  12. Yon, J.-H., 'Resistance Curves of Concrete CLWL-DCB Specimens,' Journal of the Korea Concrete Institute, Vol.14, No.3, 2002, pp.357~364 https://doi.org/10.4334/JKCI.2002.14.3.357
  13. Yon, J.-H., Hawkins, N. M., and Kobayashi, A. S., 'Comparisons of concrete fracture models,' Journal of Engineering Mechanics, ASCE, Vol.123, No.3, 1997, pp.196~203 https://doi.org/10.1061/(ASCE)0733-9399(1997)123:3(196)
  14. Navalurkar, R. K., Hsu, C. T. T., Kim, S. K., and Wecharatana, M., 'True Fracture Energy of Concrete,' Materials Journal, ACI, Vol.96, No.2, 1999, pp.213~225