A quality control framework for digital fabrication with concrete

The quality control of digital fabrication with concrete has more stringent requirements than traditional casting. Firstly, since formwork is typically absent, or removed at an early stage in production, the material is exposed to external influences that can result in deformations, collapse, or deterioration. Therefore, the evolution of properties during the process has to be controlled. Secondly, the fabrication systems are typically more sensitive to dosing fluctuations, and the produced, optimized objects are more sensitive to defects, which requires the process variations to be controlled at a higher resolution. A framework is presented that categorizes quality control experiments into destructive and non-destructive, according to their systematic error, and according to the location of testing with respect to the process. This framework is applied to the fresh state mechanical performance of concrete and quality control strategies are derived from it. Lastly, research gaps are identified that are critical for the further development and adoption of these quality control strategies in digitally fabricated concrete

A quality control framework for digital fabrication with concrete

The quality control of digital fabrication with concrete has more stringent requirements than traditional casting. Firstly, since formwork is typically absent, or removed at an early stage in production, the material is exposed to external influences that can result in deformations, collapse, or deterioration. Therefore, the evolution of properties during the process has to be controlled. Secondly, the fabrication systems are typically more sensitive to dosing fluctuations, and the produced, optimized objects are more sensitive to defects, which requires the process variations to be controlled at a higher resolution. A framework is presented that categorizes quality control experiments into destructive and non-destructive, according to their systematic error, and according to the location of testing with respect to the process. This framework is applied to the fresh state mechanical performance of concrete and quality control strategies are derived from it. Lastly, research gaps are identified that are critical for the further development and adoption of these quality control strategies in digitally fabricated concrete

An in-line dye tracer experiment to measure the residence time in continuous concrete processing

This paper introduces an in-line dye tracer experiment to measure the residence time functions in continuous concrete processing. These functions quantify the material-system interdependency and can be used to compare different material-system combinations and for quality and process control. A Rhodamine B solution was used as the tracer material and detected by measuring the color intensity using a digital image processing technique. The experiment was validated on a 3D concrete printing system by comparing the results of impulse, step-up and step-down inputs with different tracer quantities. The results show that a high signal-to-noise ratio can be obtained with low tracer concentrations. For the examined combination of material and system, an impact on the original process was only observed for the step-up inputs at high tracer quantities. It is concluded that the presented method is cost-effective and non-labor-intensive and, therefore, has the potential for wide adoption and integration in automated workflows

BioMat pavilion 2018:Development, fabrication and erection of a double curved segmented shell from biocomposite elements

Bio-based composite materials in architecture have gained various new applications due to their availability, renewability, and environmentally-friendly characteristics. This paper demonstrates the use of bio-based building materials for load-bearing structures through a 1:1 realized segmented shell pavilion, referred to as BioMat Pavilion 2018. The pavilion consisted of 121 parametrically optimized curved elements prepared by a vacuum-assisted veneer-reinforcement lamination process. The biocomposite panels were fabricated from elastic or flexible fibreboards applied as sandwich cores laminated with veneer from both sides to provide elevated stiffness. Digitally prefabricated elements were bolted together on site into four shell segments, which were later lifted up and screwed, to three curved timber-intersecting beams, fixed to three footing foundations. In this paper analysis method, form-finding hierarchy and construction stages of the 3.6 m height, 9.5 m span, covering an area of around 55m2 are discussed.</p

BioMat pavilion 2018: Development, fabrication and erection of a double curved segmented shell from biocomposite elements

Bio-based composite materials in architecture have gained various new applications due to their availability, renewability, and environmentally-friendly characteristics. This paper demonstrates the use of bio-based building materials for load-bearing structures through a 1:1 realized segmented shell pavilion, referred to as BioMat Pavilion 2018. The pavilion consisted of 121 parametrically optimized curved elements prepared by a vacuum-assisted veneer-reinforcement lamination process. The biocomposite panels were fabricated from elastic or flexible fibreboards applied as sandwich cores laminated with veneer from both sides to provide elevated stiffness. Digitally prefabricated elements were bolted together on site into four shell segments, which were later lifted up and screwed, to three curved timber-intersecting beams, fixed to three footing foundations. In this paper analysis method, form-finding hierarchy and construction stages of the 3.6 m height, 9.5 m span, covering an area of around 55m2 are discussed

Mechanical behavior of printed strain hardening cementitious composites

Extrusion based additive manufacturing of cementitious materials has demonstrated strong potential to become widely used in the construction industry. However, the use of this technique in practice is conditioned by a feasible solution to implement reinforcement in such automated process. One of the most successful ductile materials in civil engineering, strain hardening cementitious composites (SHCC) have a high potential to be employed for three-dimensional printing. The match between the tailored brittle matrix and ductility of the fibres enables these composites to develop multiple cracks when loaded under tension. Using previously developed mixtures, this study investigates the physical and mechanical performance of printed SHCC. The anisotropic behavior of the materials is explored by means of mechanical tests in several directions and micro computed tomography tests. The results demonstrated a composite showing strain hardening behavior in two directions explained by the fibre orientation found in the printed elements. Moreover, the printing technique used also has guaranteed an enhanced bond in between the printed layers.Materials and Environmen