Predicting the printability of concrete structures

The influence of temperature on the mechanical properties of fresh concrete and numerical modelling of the 3D printing process

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Abstract

In this thesis a parametric finite element model has been developed to predict the printability of concrete structures of arbitrary geometries. The model can be used to effectively explore design and process parameters to optimize printed objects. In addition, the model can be used to improve the reliability of the printing process, reduce the number of failures during production and enhance the production capabilities of complex geometries. A comprehensive experimental programme was designed in which uniaxial compression tests have been performed to determine the development of the mechanical properties of the concrete during the printing process. A novel method was created by which test samples could be extracted directly from printed concrete in order to incorporate the influence of the full printing process on the properties of the concrete. Moreover, from both literature and the valuable experience in printing of Bruil it was known that the temperature of the concrete mix can have a major influence on the mechanical properties of concrete. Therefore, the performance of the concrete under elevated temperatures was included in the research too. On top of that, printing experiments were conducted in which two geometries were printed multiple times to characterize the reliability of the printing process, and to verify the finite element models with.