Mechanical properties and failure criterion of ultra-high performance concrete under tri-axial compression
To study the tri-axial compressive mechanical properties and failure criteria of ultra-high performance concrete(UHPC),considering influence factors in terms of confining pressure,volume fraction of steel fiber(SF),aspect ratio of SF and volume fraction of polypropylene fiber(PF),a total of 39 UHPC cylinder specimens were fabricated.Through the conventional tri-axial compression tests,the tri-axial failure mode of UHPC was investigated,the tri-axial stress-strain curve was analyzed,the change law of strength and deformation performance indexes was revealed,and a multiaxial failure criterion of UHPC considering fiber parameters was proposed.Test results indicated that all specimens exhibit shear failure under tri-axial stress,and confining pressure has great effect on the formation and distribution of cracks.The whole tri-axial compression process includes linear elastic section,nonlinear hardening section,and strain softening section.The application of confining pressure and the inclusion of SF can significantly improve the mechanical properties of UHPC under tri-axial compression.As confining pressure increases from 0 MPa to 40 MPa,peak stress and strain increase by up to 161.7％and 224.7％,respectively.As the volume fraction of SF increases from 0％to 3％and the aspect ratio increases from 30 to 80,peak stress and strain increase by up to 24.6％and 68.6％,respectively.Meanwhile,the addition of PF contributes to the deformation capacity of UHPC.The confining pressure has the greatest influence on the mechanical properties of tri-axial compression,followed by the SF and then the PF.The failure criterion for UHPC was established based on Willam-Warnke five-parameter model.The model predictions are in good agreement with existing experimental results.
ultra high performance concretetri-axial compressionhybrid fiberstress-strain relationfailure criterion
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万方数据
维普
