Fracture characteristics and parametric analysis of high strength concrete
In order to investigate the fracture characteristics of high strength concrete(HSC),three-point bending test was performed on HSC beams with centre-notched,and the extended finite element method(XFEM)was employed to simulate the beams.The horizontal strain fields of the beams in different loading stages were obtained by digital image correlation technique(DIC).In addition,an analysis of the effect of the seam height ratio a0/D and the span S on the fracture characteristics was conducted with XFEM models.The results show that the simulated load-crack opening displacement(P-s)curve is basically consistent with the experimental results in the loading stage,but smaller than the experimental results in the unloading stage.The simulated critical effective crack length ac,initiation load Pini,peak load Pun,crack opening displacement under peak loads,initiation fracture toughness KiniIC,and instability fracture toughness KunIC are roughly in accordance with the experimental results.Therefore,the P-s curve and fracture parameters measured by XFEM are consistent with those obtained by the test respectively,and the XFEM models can preferably simulate the fracture behavior of HSC.During the experiment process,the crack path is irregular,while in the numerical simulation,the cracks basically extend in a straight line.As a0/D increases,the initiation load Pini,peak load Pmax and instability fracture toughness KunIC decrease,and the initiation instability toughness KiniIC basically unchanges.With the increase of S,the initiation load Pini and peak load Pmax decrease and the instability fracture toughness KunIC increase,while the initiation instability toughness KiniIC basically stays unchanged.
high strength concretefracture characteristicnumerical analysisthree-point ben-ding beam
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