Abstract: This paper presents a systematic study of flexural tensile tests on flexural tensile strength, mid-span deflection at peak load, and toughness of plastic concrete, influenced by fiber type, fiber content, fly ash content, and silica fume content. The results indicate that flexural tensile strength and deformation properties could be improved to some extent by adding fibers, fly ash or silica fume into the plastic concrete. With fiber content increasing up to 0.9 kg/m3, all the flexural tensile strength, peak load mid-span deflection, and area under flexural tensile load-deflection curve were increased, while these three parameters decreased when the content exceeded 0.9 kg/m3. The secant modulus at peak load was reduced to different degrees with different fiber contents, and reached the minimum at the content of 0.9 kg/m3. Adding fly ash within some content increased all the three parameters and reduced the secant modulus at peak load. With an increase in silica fume content, all the three parameters were increased, but a pinch phenomenon became obvious in the load-deflection curve . By analysis on the test results, we formulated a new formula for calculation of toughness and an equation of load-deflection curve.