In order to study the effect of fibers to the anti-crack performance of the concrete, sixteen different plat restraint specimens with four different fiber mixing amount (steel fiber is 0, 0.5%, 1%, 1.5%, and polypropylene fiber is 0, 0.1%, 0.2%, 0.3% respectively), are selected to comparison about the influence on the anti-cracking property of the hybrid fiber concrete, single fiber reinforced concrete and plain concrete. Experiments show that fibers increasing the anti-crack performance of the concrete significantly. The relationship between f...