Influence of Fiber Orientation on the Elastic Limit Tensile Stress of UHPFRC

The elastic limit tensile stress of UHPFRC is governed by contributions of the cementitious matrix and the fibrous skeleton. This paper finds that fiber orientation has significant influence on the matrix tensile strength of UHPFRC, while this is not considered in current estimation of elastic limit tensile stress. An original model relating fiber orientation to the elastic limit tensile stress is proposed. Uniaxial tensile tests have been conducted on ten dumbbell-shaped specimens, whose local fiber volume and orientation are determined using a magnetic probe before testing. Based on the results of local fiber distribution, the influence of fiber orientation on the elastic limit tensile stress is discussed, showing that the proposed model estimates well the elastic limit tensile stress of UHPFRC.