Determining residual double-K fracture toughness of post-fire concrete using analytical and weight function method

Determination of double-K fracture parameter using both analytical and weight function method is carried out in present research. In calculating the cohesive fracture toughness, two situations are divided at critical load. Wedge-splitting tests with ten temperatures varying from 20 to 600 °C are implemented. The complete load-crack opening displacement curves are obtained from which the initial and critical fracture toughness could be calculated experimentally. The validation of double-K fracture model to the post-fire concrete specimens is proved. Meanwhile the weight function method agrees well with the analytical method. Finally, an index to indicate the brittleness of concrete specimen through the ratio of initial fracture toughness and unstable fracture toughness is proposed.

[1]  D. Munz,et al.  On the calculation of crack opening displacement from the stress intensity factor , 1987 .

[2]  H. Reinhardt,et al.  Determination of double-K criterion for crack propagation in quasi-brittle fracture, Part III: Compact tension specimens and wedge splitting specimens , 1999 .

[3]  Chris J. Pearce,et al.  Residual fracture properties of normal- and high-strength concrete subject to elevated temperatures , 2000 .

[4]  Surendra P. Shah,et al.  Two Parameter Fracture Model for Concrete , 1985 .

[5]  P. Petersson.  Crack growth and development of fracture zones in plain concrete and similar materials , 1981 .

[6]  Surendra P. Shah,et al.  A Fracture toughness criterion for concrete , 1985 .

[7]  H. Bueckner.  NOVEL PRINCIPLE FOR THE COMPUTATION OF STRESS INTENSITY FACTORS , 1970 .

[8]  Nenad Bićanić,et al.  Fracture energy of high-performance concrete at high temperatures up to 450°C : the effects of heating temperatures and testing conditions (hot and cold) , 2006 .

[9]  J. Achenbach,et al.  COMPUTATION OF THE WEIGHT FUNCTION FROM A STRESS INTENSITY FACTOR. , 1977 .

[10]  Pere C. Prat,et al.  Effect of Temperature and Humidity on Fracture Energy of Concrete , 1988 .

[11]  Shailendra Kumar,et al.  Influence of specimen geometry and size-effect on the KR-curve based on the cohesive stress in concrete , 2008 .

[12]  Z. Bažant,et al.  Determination of fracture energy, process zone longth and brittleness number from size effect, with application to rock and conerete , 1990 .

[13]  Hans W. Reinhardt,et al.  Tensile Tests and Failure Analysis of Concrete , 1986 .

[14]  G. Glinka,et al.  Universal features of weight functions for cracks in mode I , 1991 .

[15]  C. V. Nielsen,et al.  Residual fracture energy of high-performance and normal concrete subject to high temperatures , 2003 .

[16]  Shailendra Kumar,et al.  Influence of specimen geometry on determination of double-K fracture parameters of concrete: a comparative study , 2008 .

[17]  Shailendra Kumar,et al.  Determining the double‐K fracture parameters for three‐point bending notched concrete beams using weight function , 2010 .

[18]  H. K. Hilsdorf,et al.  Code-type formulation of fracture mechanics concepts for concrete , 1991 .

[19]  T. Fett.  Limitations of the petroski-achenbach procedure demonstrated for a simple load case , 1988 .

[20]  Leon M Keer,et al.  Stress Intensity Factors Handbook, Vol. 3 , 1993 .

[21]  Surendra P. Shah,et al.  Softening Response of Plain Concrete in Direct Tension , 1985 .

[22]  D. V. Phillips,et al.  Direct tension tests on notched and un-notched plain concrete specimens , 1993 .

[23]  H. Reinhardt,et al.  Determination of double-Determination of double-K criterion for crack propagation in quasi-brittle fracture Part I: experimental investigation of crack propagation , 1999 .

[24]  Sudhirkumar V. Barai,et al.  Determining double-K fracture parameters of concrete for compact tension and wedge splitting tests using weight function , 2009 .

[25]  A. Hillerborg,et al.  Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements , 1976 .

[26]  Hiroshi Tada,et al.  The stress analysis of cracks handbook , 2000 .

[27]  S. Hamoush,et al.  Variation of the fracture toughness of concrete with temperature , 1997 .

[28]  Bhushan Lal Karihaloo,et al.  Determination of specimen-size independent fracture toughness of plain concrete , 1986 .

[29]  H. Reinhardt,et al.  Determination of double-K criterion for crack propagation in quasi-brittle fracture, Part II: Analytical evaluating and practical measuring methods for three-point bending notched beams , 1999 .

[30]  Shailendra Kumar,et al.  Size-effect Prediction from the Double-K Fracture Model for Notched Concrete Beam , 2010 .

[31]  G. Baker.  The effect of exposure to elevated temperatures on the fracture energy of plain concrete , 1996 .

[32]  B. Karihaloo,et al.  Size-effect prediction from effective crack model for plain concrete , 1990 .

[33]  J. Rice,et al.  Some remarks on elastic crack-tip stress fields , 1972 .

[34]  Z. Bažant,et al.  Crack band theory for fracture of concrete , 1983 .

[35]  Y. Murakami.  Stress Intensity Factors Handbook , 2006 .