Cementitious materials for construction-scale 3D printing: Laboratory testing of fresh printing mixture

This study presents the development of fly ash-based geopolymer mixtures for 3D concrete printing. The influence of up to 10% ground granulated blast-furnace slag (GGBS) and silica fume (SF) inclusion within geopolymer blends cured under ambient conditions was investigated in terms of fresh and hardened properties. Evolution of yield stress and thixotropy of the mixtures at different resting times were evaluated. Mechanical performance of the 3D printed components was assessed via compressive strength measurements and compared with casted samples. SF demonstrated a significant influence on fresh properties (e.g. recovery of viscosity), whereas the use of GGBS led to higher early strength development within geopolymer systems. The feasibility of the 3D printing process, during which rheology was controlled, was evaluated by considering extrusion and shape retention parameters. The outcomes of this study led to the printing of a freeform 3D component, shedding light on the 3D printing of sustainable binder systems for various building components.

Investigation of the rheology and strength of geopolymer mixtures for extrusion-based 3D printing

Additive manufacturing as an enabling technology for digital construction: A perspective on Construction 4.0

Effects of interlocking on interlayer adhesion and strength of structures in 3D printing of concrete

Digital construction is gradually opening unlimited possibilities for building and concrete industry. The key secret for a robust print process lies in our understanding of the processing technology and material fresh properties, in addition to developing novel measurement and control techniques. This paper aims to gain a better understanding of early age mechanical properties of 3D printable materials and improve it for the requirement of large scale concrete printing. Experimental investigations were carried out to measure green strength and stiffness of fresh fly ash-cement mortar with applied 3D optical metrology. The compressive green strength was linked with material yield strength evolution and later, modified with nanoclay for higher buildability properties. Nanoclay addition deceased the layer deformation due to significant increase in Young's modulus and to estimate this uncontrolled deformation, a mathematical function was formulated, which subsequently validated by comparison to printing experiments.

Mechanical properties and deformation behaviour of early age concrete in the context of digital construction

Purpose




This paper aims to report on the experiments with the Contour Crafting Automated Construction process using sulfur concrete as the choice of construction material.




Design/methodology/approach




Several experiments have been performed at centimeter and meter scales. A finite element analysis simulation model for the behavior of sulfur concrete-based structures has been developed. Experimental results were compared with the results of simulation.




Findings




Sulfur concrete has numerous terrestrial applications and is potentially an ideal construction material for planetary construction.




Originality/value




Experimental samples of sulfur concrete were fabricated using a novel mixer/extrusion system. The mechanism was proven to be durable and stable after more than 500 h of work.

Construction by Contour Crafting using sulfur concrete with planetary applications

This paper reports on the experiments with the Contour Crafting Automated Construction process using sulfur concrete as the choice of construction material. Sulfur concrete has numerous terrestrial applications and is potentially an ideal construction material for planetary construction. On Mars, sulfur can be found in abundance and the range of temperature variation on the planet is within the safe zone for the structures to be built and survive over reasonable length of time with sulfur concrete. Several experiments have been performed at centimeter and meter scales. A FEA simulation model for the behavior of sulfur concrete based structures has been developed. Experimental results were compared with the results of simulation.

http://aicservices.info/SNUSDOC/051216SN-01%20%2016-0107%20%20GEOK%20KIAW.pdf

Bin Xia

Papers

Construction by Contour Crafting using sulfur concrete with planetary applications

Deformation Analysis of Sulfur Concrete Structures Made by Contour Crafting