Investigation on compressive behaviors of thermoplastic pipe confined concrete

Thermoplastic pipe confined concrete (TPCC) is a composite system that uses thermoplastic pipe to confine the concrete bridge pier columns. TPCC aims at piers exposed to the tidal zone or the air–earth zone in marine and saline environments, and protects them from salt damages due to isolate them from the aggressive substances and to eliminate the zones of the concrete structure. PVC pipes were chosen to make TPCC in this paper. Compressive behavior like ultimate strength, stress–strain curve, ductility and toughness of TPCC and effects of plastic pipe thickness, the cubic compressive strength of core concrete (fcu) on them were investigated in this paper. Results indicate: (1) TPCC overcomes the shortcomings of the common concrete greatly, such as high brittleness and bad ductility. The strain at peak stress of TPCC are 1.415–5.540 times higher than the common concrete, meanwhile, the energy absorption of TPCC are 14.8–38.8 times higher than the common concrete. (2) The pipe thickness and fcu have significant effects on onset behavior and post-peak behavior of the stress–strain curves and the ultimate strength of TPCC. (3) Effect of pipe thickness on ultimate strength of the specimens with same core concrete is not unique. In addition, ultimate strength of the specimens with same pipe increases with the increase of fcu.