Investigation of concrete mixtures for additive construction

Abstract

Purpose This paper aims to qualify traditional concrete mixtures for large-scale material extrusion in an automated, additive manufacturing process or additive construction. Design/methodology/approach A robust and viable automated additive construction process must be developed that has the capability to construct full-scale, habitable structures using materials that are readily available near the location of the construction site. Accordingly, the applicability of conventional concrete mixtures for large-scale material extrusion in an additive construction process was investigated. A qualitative test was proposed in which concrete mixtures were forced through a modified clay extruder and evaluated on performance and potential to be suitable for nozzle extrusion typical of additive construction, or 3D printing with concrete. The concrete mixtures were further subjected to the standard drop table test for flow, and the results for the two tests were compared. Finally, the concrete mixtures were tested for setting time, compressive strength and flexural strength as final indicators for usefulness in large-scale construction. Findings Conventional concrete mixtures, typically with a high percentage of coarse aggregate, were found to be unsuitable for additive construction application due to clogging in the extruder. However, reducing the amount of coarse aggregate provided concrete mixtures that were promising for additive construction while still using materials that are generally available worldwide. Originality/value Much of the work performed in additive manufacturing processes on a construction scale using concrete focuses on unconventional concrete mixtures using synthetic aggregates or no coarse aggregate at all. This paper shows that a concrete mixture using conventional materials can be suitable for material extrusion in additive construction. The use of conventional materials will reduce costs and allow for additive construction to be used worldwide.

Review of Emerging Additive Manufacturing Technologies in 3D Printing of Cementitious Materials in the Construction Industry

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A review of 3D concrete printing systems and materials properties: current status and future research prospects

“…Typically, in most cases the maximum sand particle size was limited to less than 2 mm (WinSun, 2018;Nerella et al, 2016;Perrot et al, 2016;Visser, 2007;Anell, 2015;Le et al, 2012b;Malaeb et al, 2015). However, coarse aggregate with particle size up to 10 mm have been used in 3DPC (Rushing et al, 2017). To control the open time and setting period of the materials, superplasticizer (SP), accelerator and retarder were also used in the mixes.…”

Strength Development Characteristics of SBR-Modified Cementitious Mixtures for 3-Demensional Concrete Printing

“…Consequently, research is underway worldwide to develop concrete printing materials applicable to the 3DCP process [2]. Recent studies on such materials have used ordinary Portland cement as basic material and were conducted using silica fume [6][7][8], fly ash [1,9,10], and silica fume and fly ash [10,11], but no work to date has used water-soluble polymers, such as styrene-butadiene rubber (SBR) as modifiers.…”