Fatigue crack growth analysis of fiber reinforced concrete with effect of interfacial bond degradation

Abstract

This paper presents an analytic model for fatigue crack life prediction in fiber reinforced concrete (FRC). The model elucidates fatigue crack growth in cementitious matrix material under the influence of external cyclic load and fiber and aggregate bridging. It is shown that fiber-matrix interface damage is necessary to properly simulate the three experimentally observed stages of matrix crack growth, involving a decelerated stage, a steady state stage, and an accelerated stage towards final fracture failure. This model, which explicitly accounts for the positive role of fiber on fatigue life, predicts the existence of the well known fatigue limit load in standard S-N curve tests of FRCs. The basic framework of this analysis can be used to address fatigue life of FRC structures subjected to high cycle fatigue loading, as well as providing a basis for material design of fatigue resistant FRC at the microstructure level.

Fatigue life analysis of fiber reinforced concrete with a fracture mechanics based model

“…Theoretical S-N diagrams of FRCs can be generated with a fracture mechanics based model that showed agreement with experimental data in three distinct stages of fatigue crack growth of an FRC 6 . The model predicts the number of cycles to failure which is defined by final failure subsequent to fatigue crack growth, accounting for the effect of cycledependent crack bridging, and it is expressed explicitly in terms of microstructural parameters of FRCs (for example, fiber length, fiber diameter, fiber modulus, fiber volume fraction, and interfacial bond strength).…”

“…The fracture mechanics based fatigue model of randomly distributed discontinuous fiber composites developed by Li and Matsumoto 6 is summarized in this section. Details of the model can be found in Li and Matsumoto 6 , Matsumoto and Li 7 , and Wu et al 8 .…”

“…Details of the model can be found in Li and Matsumoto 6 , Matsumoto and Li 7 , and Wu et al 8 . The fatigue life model is based on fracture mechanics of fatigue crack growth of FRCs.…”

“…The model predicts the number of cycles to failure which is defined by final failure subsequent to fatigue crack growth, accounting for the effect of cycledependent crack bridging, and it is expressed explicitly in terms of microstructural parameters of FRCs (for example, fiber length, fiber diameter, fiber modulus, fiber volume fraction, and interfacial bond strength). In this paper, the theoretical S-N diagram of four different FRCs has been obtained with the model presented in Li and Matsumoto 6 . It shows that a simple assumption pertaining to the cycle-dependent degradation of crack bridging explains a wide range of experimental results reported in the literature and that the modification of fiber-matrix interface may lead to fatigue life improvement.…”

Mechanisms of Multiple Cracking and Fracture of DFRCC under Fatigue Flexure

“…However, for this to take place under bridging stress degradation (Li et al 1998), probably a more severe multiple cracking condition has to be met.…”