Transition from Fluid to Solid Concrete in the Flexible Mould Process

Abstract

The transition period between the mixing of concrete and the begin of setting increasingly receives attention, as special production processes can be developed with tailor-made fresh state characteristics. In this publication the two processes of 3D Concrete Printing (3DCP) and the production with the Flexible Mould Process (FMP) are discussed and compared. The FMP is a relatively new manufacturing method that was developed to allow the efficient production of curved thin concrete panels for cladding or structural use. The term ‘flexible’ refers to the deformation into the required curved shape of both the compliant mould surface and the fresh concrete contained by the mould shortly after casting. After that deformation, both the mould and the concrete are left for further hardening until demoulding is possible. The development of the 3DCP technique progresses fast, hereby new perspectives are gained with regard to mix design, production and structural performance. Sideway, test methods need to be developed or re-evaluated. The early age strength and strain capacity are important parameters for both processes, although they are not the same with regard to magnitude, period or time after mixing. Both processes can be executed within an open window and with specific boundary conditions only. This publication discusses and compares both processes. The implications of these recent findings are translated to practical aspects with regard to the production with the FMP.