Journal ArticleDOI
Effect of flow behavior and process-induced variations on shape stability of 3D printed elements – A review
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TLDR
In this paper, a comprehensive review of material flow behavior during pumping and extrusion is discussed, and its influence on shape stability of 3D printed elements is highlighted. But only limited emphasis exists on flow behavior and process-induced variations in material properties during printing.Abstract:
Successful implementation of extrusion-based 3D printing (3DP) of concrete requires knowledge of material flow behavior during pumping and extrusion and its influence on shape stability of printed elements. Limited emphasis exists on flow behavior and process-induced variations in material properties (rheology and composition) during printing. This paper delineates the effect of flow behavior and process-induced variations on shape stability. A comprehensive review of material flow behavior during pumping and extrusion is discussed, and its influence on shape stability of 3DP elements is highlighted. The extent of shearing in print material is shown to govern process-induced variations during pumping and extrusion. During extrusion, the degree of filtration and consolidation plays a significant role on shape stability. Accurate assessment of process-induced changes in material properties is required to ensure steady and continuous flow of material during 3DP and secure proper shape stability of printed elements.read more
Citations
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Journal ArticleDOI
3D Concrete Printing: A Systematic Review of Rheology, Mix Designs, Mechanical, Microstructural, and Durability Characteristics
Atta Ur Rehman,Jung-Hoon Kim +1 more
TL;DR: In this paper, the authors provide a state-of-the-art report on the up-to-date research on the emerging 3D concrete printing technology from the concrete materials perspective.
Journal ArticleDOI
The relationship between the rheological behavior and interlayer bonding properties of 3D printing cementitious materials with the addition of attapulgite
TL;DR: In this paper , the relationship between the rheological behavior of 3D printing concrete and the interlayer bonding strength and durability was studied. And an empirical formula combining interlayer strength with the dynamic yield stress and the structural build-up rate was proposed for 3DPC, considering porosity and hydration degree.
Journal ArticleDOI
The relationship between the rheological behavior and interlayer bonding properties of 3D printing cementitious materials with the addition of attapulgite
TL;DR: In this article, the relationship between the rheological behavior of 3D printing concrete and the interlayer bonding strength and durability was studied. And an empirical formula combining interlayer strength with the dynamic yield stress and the structural build-up rate was proposed for 3DPC, considering porosity and hydration degree.
Journal ArticleDOI
Rheology and printability of Portland cement based materials: a review
TL;DR: In this paper , the authors provide a comprehensive analysis of the rheology of Portland cement-based materials used in extrusion-based 3D concrete printing, focusing on the influence of mix design on the required 3DCP in both fibre reinforced and non-fibre reinforced mixtures.
Journal ArticleDOI
Relationship between microstructure and strain-hardening behaviour of 3D printed engineered cementitious composites
TL;DR: In this paper , the macroscopic mechanical properties of normal and printed ECC with various polyethylene (PE) fiber lengths (6 and 12 mm) in relation to their microstructural features in terms of pore structure characteristics, fibre orientation and fibre dispersion through a series of mechanical tests and X-ray computed tomography (CT) and backscattered electron (BSE) image acquisition, processing and analysis.
References
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Automated construction by contour crafting—related robotics and information technologies
TL;DR: Contour crafting (CC) is a recent layered fabrication technology that has a great potential in automated construction of whole structures as well as subcomponents and will most probably be one of the very few feasible approaches for building structures on other planets, such as Moon and Mars.
Journal ArticleDOI
Mix design and fresh properties for high-performance printing concrete
Thanh T. Le,Thanh T. Le,Simon A. Austin,Sungwoo Lim,Richard A. Buswell,Alistair G.F. Gibb,Tony Thorpe +6 more
TL;DR: In this article, the authors present the experimental results concerning the mix design and fresh properties of a high-performance fiber-reinforced fine-aggregate concrete for printing concrete, which has been designed to be extruded through a nozzle to build layer-by-layer structural components.
Journal ArticleDOI
Hardened properties of high-performance printing concrete
Thanh T. Le,Simon A. Austin,Sungwoo Lim,Richard A. Buswell,R. Law,Alistair G.F. Gibb,Tony Thorpe +6 more
TL;DR: In this paper, the authors presented the hardened properties of a high-performance fiber-reinforced fine-aggregate concrete extruded through a 9mm diameter nozzle to build layer-by-layer structural components in a printing process.
Journal ArticleDOI
The origins of thixotropy of fresh cement pastes
TL;DR: In this article, a detailed analysis of the macroscopic behavior of fresh cement pastes is presented, showing that the largest critical strain can be associated with the network of colloidal interactions between cement particles and the smallest critical strain is associated with early hydrates, which form preferentially at the contact points between cement grains.
Journal ArticleDOI
A thixotropy model for fresh fluid concretes: Theory, validation and applications
TL;DR: In this article, the methods used to measure and model thixotropy of fresh concrete in the civil engineering field are described and a simple thixotropic model is presented, which is in agreement with the experimental observations that can be found in the literature.