The use of stay-in-place (SIP) formwork has become an increasingly popular tool for concrete structures, providing advantages in construction scheduling and labor reduction. Previous research suggests that PVC provides an enhancement to reinforced concrete strength and ductility. The research herein outlines tests on reinforced concrete walls with a compressive strength of 25 MPa, utilizing two types of PVC panels: flat or hollow, in order to further understand the polymer's contribution to flexural resistance. Variables studied included concrete core thickness (152 mm, 178 mm, and 203 mm), reinforcing ratio (3-10 M bars or 3-15 M bars), and panel type (hollow or flat). The walls were tested in four point bending. Walls failed due to steel yielding followed by concrete crushing, PVC buckling, and/or PVC rupture depending on the reinforcement ratio and panel type. The hollow panel encased specimens also experienced slip of the panels on the tensile face. The PVC encasement enhanced the yield load, ultimate load, ductility, and toughness of the concrete walls. Concrete cores were taken from the tested PVC encased specimens and compressive strength was found to be the same as the control walls.
Scott, B., Wahab, N., Al-Mayah, A., & Soudki, K. A. (2016). Effect of stay-in-place PVC formwork panel geometry on flexural behavior of reinforced concrete walls. Structures, 5, 123–130. https://doi.org/10.1016/j.istruc.2015.09.005