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Project

A feasibility study on the use of fine recycled aggregates in 3D printing concrete

Due to the highly specific printing process in 3D concrete printing (3DCP), the concrete mixtures used during printing need a time-dependent shear thinning property, also named thixotropic behaviour. This particular rheological behaviour of 3D printing concrete is mainly achieved by the addition of nano clay, silica fume and viscosity modifying agents (VMA), which are polluting, expensive or scarce. Finding other methods or materials to achieve this specific rheological behaviour is thus of major importance for the future applicability of 3DCP. Therefore, the hypothesis of this project states that fine recycled aggregates (FRA) can be used as replacement of fine natural aggregates in 3D printing concrete to achieve the required rheological properties. The micro geometrical shape and size distribution of the FRA caused by the crushing process can increase the mixture's internal friction and re-flocculation rate, yielding an improved thixotropic behaviour. In addition, the high water absorption can be used to reduce the free water over time, causing a faster increase in stiffness. In this project, experimental data and theoretical models will be used to assess the influence of FRA on the rheological properties of 3D printing concrete. Microstructural analyses of several types of FRA will be used to set requirements for the aggregates. In addition, a thixotropy model for 3D printing concrete incorporated with FRA will be developed. 

Date:3 Sep 2020 →  Today
Keywords:3D printing, Recycled materials, Concrete, Mortar, Grout
Disciplines:Construction materials
Project type:PhD project