Mechanical behaviors of the thin-walled SHCC pipes under compression

The buried concrete pipelines often suffer from breakage or burst due to the heavy traffic load on the pavement or earthquake. The resistance of brittle failure of concrete pipes can be improved by using strain hardening cement-based composites (SHCC), a kind of a high performance ductile composite with a tensile strain capacity exceeding 4%. In this paper, PVA fiber reinforced concrete is used to prepare SHCC and thin-walled pipes. By means of direct tension test, it is shown that the material has high ductility and high tension strength. Under three point compression test, SHCC pipe has higher loading capacity than the ordinary concrete pipe. The deformation process of SHCC pipes can be divided into three phases, that is, the elastic phase, cracking phase and the strain-hardening phase. In the latter two phases, there are multiple narrow cracks happened on the inner side of the top and bottom pipe, and the outer side of the central part of the pipe. However, the load applied on the pipe can be sustained. Under compression, the load is in good linear relationship with deflection, ring stiffness decreases with increasing load.