Crack development characteristic of PHC pipe pile in splitting test

Abstract:

A special splitting test method has been introduced for PHC300 (prestress high concrete) pipe pile to research the characteristics of crack development due to the toroidal pressure. This crack generation method is considered to be the most negative situation for PHC300 pipe pile since the crack around steels can often be observed. The results show that crack depth increases with crack width in outer surface of PHC. The crack runs through the wall thickness of PHC as the measured crack width reach to 0.18 mm in outer concrete surface and 0.1 mm in inner surface, respectively. This is probably due to the crack extensibility, i.e., inner surface has a better extensibility than outer surface because cement paste layer and mortar layer tend to integral fracture in inner surface. Compared with a solid concrete structure, the crack in PHC is seemly difficult to recovery due to a relatively small bonding area in outer concrete surface contributed by the hollow structure. Crack recovery values increase with the increase of crack widths in outer surface, while crack recovery rates is opposite. The recovery rates of crack open displacement (COD) in outer surface are generally below 50％.