Research on the Multi-Functional Composite Stay-in-Place Insulated Formwork for Concrete Dams in Cold Regions

This research presents a new type of composite stay-in-place (SIP) formwork for concrete dams in cold regions of China. The formwork module is high-strength concrete with sprayed polyurethane to provide heat insulation. It features a ribbed-slab structural pattern, which ensures a reasonable stress distribution and an acceptable level of maximum tensile stress. The formwork modules can be conveniently assembled on-site to form the molds for casting dam concrete, and due to the secure embedment of the module nodal legs into the dam, the ice-plucking delamination issue of the sprayed polyurethane boards commonly seen in the concrete dams in cold regions can be avoided. Besides heat insulation, this SIP formwork can also perform as a face cover to protect the dam concrete from ambient erosions, which requires the concrete to have excellent durability and good ductility. To fulfill this task, two types of high-strength concrete are proposed.