Rheological parameters used for deliberate deformation of a flexible mould after casting

Abstract

This paper describes how curved precast concrete elements can be manufactured in an open and reusable flexible mould. The proposed method reduces formwork costs of architectural freeform elements in concrete. First, the method is described briefly, then a series of tests are discussed, demonstrating that by measuring the rheological parameters ofthe mixture during the process, the right moment of deformation con be determined. The measurements show that thixotropic behavior for this manufacturing method is very helpful, since it leads to a quick increase of the yield strength of the fresh concrete, but still leaves the concretconcrete deformable in order to prevent cracking caused by the movement ofthe mould.