Boundary Effect on the True Specific Fracture Energy of Concrete


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The apparent size effect of the specific fracture energy of concrete according to the RILEM procedure has been confirmed by numerous published works. The paper offers an explanation for this size effect by considering the specimen boundary influence on local fracture energy over the ligament length, which is closely associated with the measured fracture energy of concrete. To address this boundary influence, boundary affected length is introduced, over which local fracture energy is different from that in the bulk far away from the surface of the specimen. Based on previous work, a continuous smooth function is hypothesized to simulate the distribution of local fracture energy. At the same time, the model established was compared to the existing models, i.e. Perturbed Ligament Model (PLM) and Bilinear Model (BLM). Some test results from wedge splitting specimen in the literature were used to verify these three models. The results show that the true fracture energy of concrete, irrespective of the specimen size, could be obtained from the measured values directly from RILEM, and is less sensitive to determination approach. The predicted boundary affected length when the crack reaches the specimen surface is more close to the value of the perturbation length in PLM.



Key Engineering Materials (Volumes 348-349)

Edited by:

J. Alfaiate, M.H. Aliabadi, M. Guagliano and L. Susmel




Y. H. Zhao et al., "Boundary Effect on the True Specific Fracture Energy of Concrete", Key Engineering Materials, Vols. 348-349, pp. 933-936, 2007

Online since:

September 2007




[1] Y.H. Zhao, S.L. Xu and Z.M. Wu: submitted to Journal of Materials in Civil Engineering ASCE(accepted).

[2] RILEM-Draft-Recommendation(50-FCM): Materials and Structures 18(106)(1985), p.285.

[3] P. Maturana, J. Planas and M. Elices: Engineering Fracture Mechanics Vol. 35(4/5)(1990), p.827.

[4] K. Duan, X.Z. Hu and F.H. Wittmann: Engineering Fracture Mechanics Vol. 70(2003), p.2257.

[5] X.Z. Hu, F.H. Wittmann: Engineering Fracture Mechanics Vol. 65(2000), p.209.

[6] H.M. Abdalla, B.L. Karihaloo: Magazine of Concrete Research Vol. 55(2)(2003), p.133.

[7] S.L. Xu, Y.H. Zhao and Z.M. Wu: Journal of Materials in Civil Engineering ASCE Vol. 18(6)(2006), p.817.