Evaluation of fracture energy, toughness, brittleness, and fracture process zone properties for lightweight concrete exposed to high temperatures

Author(s):  
Farshad Dabbaghi ◽  
Hossein Fallahnezhad ◽  
Sepideh Nasrollahpour ◽  
Mehdi Dehestani ◽  
Hossein Yousefpour
1998 ◽  
Vol 539 ◽  
Author(s):  
H. Kettunen ◽  
K. J. Niskanen

AbstractWe follow the accumulation of microscopic damage ahead the crack tip in paper. The fiber debonding process varies even within each specimen because of large variation in fiber and bond properties. In general, stiff and weakly bonded fibers tend to debond as a rigid body while ductile or well bonded fibers pull out gradually in a process that propagates from the crack line to the fiber ends. Particularly in the latter case the network ruptures coherently rather than through debonding of single fibers. Experimental analysis and simulations show that fracture energy correlates closely with the size of the fracture process zone (FPZ) irrespective the nature of the debonding process. Only the cases of low bonding and stiff fibers seem to make an exception in that FPZ can grow in size without a corresponding increase in fracture energy.


1995 ◽  
Vol 409 ◽  
Author(s):  
Y. Xi ◽  
F.E. Amparano ◽  
Zongjin Li

AbstractEffect of aggregate content on fracture behaviors of concrete is studied by testing on geometrically similar three-point bend beams. The results are analyzed by using a size effect method in which the fracture behavior of concrete is characterized by two parameters, fracture energy Gf and effective fracture process zone cf. Test results showed that with increasing volume fraction of aggregate in the range 45% - 75%: (1) the modulus of elasticity of concrete decreases slightly, (2) fracture energy Gf increases, but the rate is very small; (3) the size of the fracture process zone, cf, decreases, which may be explained by changes in coarseness of grain structures defined in terms of mosaic patterns.


1992 ◽  
Vol 25 (6) ◽  
pp. 319-326 ◽  
Author(s):  
X. -Z. Hu ◽  
F. H. Wittmann

2010 ◽  
Vol 24 (4) ◽  
pp. 479-486 ◽  
Author(s):  
S. Muralidhara ◽  
B.K. Raghu Prasad ◽  
Hamid Eskandari ◽  
B.L. Karihaloo

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