3D Concrete Printing for Sustainable Construction

Abstract

Despite the rapid development of 3D printing technology for cement composites, there are still a number of unsolved issues related to extrusion printing. One of them is proper mix design that allows for meeting criteria related to the printing of cementitious materials, such as pumpability, buildability, consistency on the materials, flowability and workability, simultaneously incorporating sustainable development ideas. In the case of mixes for 3D printing, the modification of the composition which increases the overall performance does not always go hand in hand with the reduction of negative environmental impact. The article presents the results of tests of eight mixtures modified with reactive and inert mineral additives designed for 3D printing. The mixes were evaluated in terms of their rheological and mechanical properties as well as environmental impact. Initial test results were verified by printing hollow columns up until collapse. Later, the differences between the compressive strength of standard samples and printed columns were determined. In order to summarize the results, a multi-faceted analysis of the properties of the mixes was carried out, introducing assessment indicators for its individual parameters. The article proves that appropriate material modification of mixes for 3D printing can significantly reduce the negative impact on the environment without hindering required 3D printing properties.

Foundation Piles—A New Feature for Concrete 3D Printers

“…Based on Table 9 , in the case of traditional shallow foundations, the concrete consumption is as much as 53.0% higher than in the case of piles that formed using a 3D printer. This results in a significant reduction in printing costs and, due to the reduced use of cement and other reactive components, has a positive impact on the environment [ 38 , 91 ]. In addition, a smaller amount of concrete directly reduces the need for formwork, which is a significant cost when erecting building structures [ 92 , 93 ].…”

“…Depending on the type of technology used for 3D printing, the mix that is intended for this purpose must have the appropriate mechanical and rheological properties. In the “Extrusion” printing method, the fresh mix must have rheological properties that will allow it to maintain its shape during the application of successive layers and, at the same time, be characterised by adequate extrudability/pumpability for the assumed period of the so-called “open time” [ 38 ]. Controlling the properties of the mix is also important in terms of its load-bearing capacity.…”

“…In the techniques described above (“extrusion,” “contour crafting”) the mix is generally designed on a cement binder with various reactive additives, such as fly ash or silica fume [ 1 , 38 , 39 , 47 , 48 , 49 ]. For technological reasons, mixes usually only contain fine aggregate [ 38 , 47 , 48 , 49 , 50 , 51 ]. The fine aggregate used is often modified with various micro-fillers to improve the rheological properties [ 52 , 53 , 54 , 55 , 56 ].…”

“…In the techniques described above ("extrusion," "contour crafting") the mix is generally designed on a cement binder with various reactive additives, such as fly ash or silica fume [1,38,39,[47][48][49]. For technological reasons, mixes usually only contain fine aggregate [38,[47][48][49][50][51].…”

Implementation of Alternative Mineral Additives in Low-Emission Sustainable Cement Composites

“…The use of alternative SCMs in concrete technology requires comprehensive research, as there are no official guidelines that would allow a straightforward assessment of their applicability. Moreover, recent research is focused also on the incorporation of mineral additives in non-standard, innovative concrete applications, such as 3D printing [ 7 , 8 , 9 ].…”