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point of view

statically, economically as well as ecologically lost. So why print 5. regulatory oBstacles
with mortars in the first place? I assume it´s not primarily an
intended ingenuity to do so but it´s simply the easiest way as Globally, building authorities rely on regional or national
it is extremely difficult to print with standard concretes. The building codes in their permitting process for constructions.
first main obstacle is sound processing of concrete with regular As of now, 3D construction printing generally is not part of any
aggregate sizes in combination with a highly precise digital layer regular building code as it is a recent technological concept.
printing process vs. a splish-splash concrete pump being in use therefore, objects or structures that have been printed in the
to fill up formwork. The challenges are beyond any comparison. public so far, needed to have some relation to a university
therefore, there is not a single off-the-shelf component project or have another kind of preliminary or experimental
available for such a 3D printing process that has intentionally status. What complicates things further is that there are many
been designed for such ends and hence it´s a time-consuming, different technological approaches in this domain and different
demanding and costly r&D process for any 3D Construction groups for different applications have used many different
Printing firm to design, test and approve of such mechanical proven and unproven materials. As long as a 3D construction
components for such very applications. naturally, it is much printing firm is unable to get a permit in a regular permitting
faster, easier and cheaper to use available industrial robots, process, there won´t be a market and hence the foundation for
special mortars and a tube as “nozzle“ to deposit the material any regular business is missing. in order to resolve this crucial
but this approach has its limitations. issue, the Contour Crafting Corporation (USA) has started
a cooperation with the International Code Council (ICC) in
4. ProductIvIty January 2019. this collaboration resulted in preparation of a
document on acceptance criteria for 3D construction printing
the second key matter is productivity of the printing process. using Contour Crafting technology (AC509). On June 4th 2019, a
this is related to the printing speed and dimensions as well committee of building officials reviewed AC509 and unanimously
as characteristics of printed layers. Low-tech solutions show approved this new acceptance criteria document. AC509 will be
printing materials exiting from a simple tube or hose. the followed by an Evaluation Report (ESR) that will serve as a basis
result is a very high number of relatively narrow and wide layers for establishing an internationally recognized permitting process
following a given path. Also, there is a certain finishing effort to for automated construction using Contour Crafting technology.
be performed. High-tech solutions show sophisticated and often
proprietary printing nozzles, which not only master a ratio of 6. general outlook
layer height to width close to 1 but also print a given wall type in
one path. Such wall types are typically either solid walls, hollow in summary, the author believes that only some of the current
walls or connected inner and other wall parts which can be filled ongoing approaches with respect to construction 3D printing will
with concrete of the same type, insulation materials or other survive and will be adopted as economically viable construction
matching materials. Apart from the productivity of the printing methods. in general, however, the author anticipates that the
process itself, it is equally important for overall productivity construction 3D printing market share will considerably grow in
whether components or whole structures are printed and the near future. the adoption of construction 3D printing will
whether this is done on-site or off-site. mainly be in the residential and commercial building sectors.

werner Heinz Bittner Master of Mechanical and Industrial Engineering, Technical
University of Vienna, is a Chief Executive Officer of Umdasch Group Ventures GmbH (Austria) and Chairman
of the Board of Directors of Contour Crafting Corporation (USA). He has held senior leadership positions
in various organisations in different industries like surface engineering, graphic arts and pharmaceutical
manufacturing.

cite this article: Bittner, W. H. (2020). “Brief overview on 3D construction printing” The Indian Concrete Journal, Vol. 94, No. 8,
pp. 75-77.

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