Research On Bending Behaviors Of Ultra-high Performance Concrete Considering Damage Effects

Ultra-High Performance Concrete(UHPC)is a new type of cementitious composites.Because of its high mechanical properties and excellent durability,UHPC never stop to facinating researchers in civil engineering.But there is still a lack of sufficient study on its structural behaviors,which limits its engineering applications.A damage-considering cell model is presented to determine the constitutive relationship of UHPC;an experimental research is performed on six plain UHPC plates and seven fiber-reinforced UHPC plates.The main works and results indicate as follows:(1)A damage-considering cell model of UHPC was established based on the Gurson's model and then the constitutive relationship was deduced.(2)A calculation model for the cracking moment of the UHPC was established.The cracking moments of both the plain UHPC plates and the reinforced ones are were calculated.The calculated moments were almost the same.(3)A calculation model for the ultimate moment of the UHPC was established.The correction factor k is introduced to consider the plastic development of the tension zone.When k=0.2,the formula can accurately predict the ultimate moment of plain UHPC plates.Furthermore,the value of k=0.5 is suitable for the fiber-reinforced UHPC plates.(4)The distributions of void fraction along the section were calculated at both the cracking stage and the ultimate bending limit state.