Abstract:To simulate high temperature effect of tunnel fires, liquefied gas burning tests were carried out. The deformation behavior of concrete pipes reinforced with steel mesh, steel fibers(SF) and polypropylene(PP) fibers at high temperature and after cooling was investigated. Variation law of temperature and temperature difference across the outside and inside layer of the pipes under high temperature were summarized. Influence of fiber type and content(by mass) on the radial deformation at high temperature and residual radial deformation after cooling was analyzed during once and twice heating cooling test. It can be concluded that, both of the temperature difference between the inside and outside layers and radial deformation of the concrete pipes reach the maximum at the end of gas temperature stable stage. The use of SF or hybrid use of SF and PP fiber has a significant effect on reduction of the maximum radial deformation of the pipes at high temperature.Residual radial deformation can be observed after the cyclic high temperature test and there exists a hybrid effect on restriction of the residual radial deformation after cooling.