Raw-Earth 3D Printing Construction Technology

New Zealand’s construction industry has frequently sought to explore new materials and technologies to achieve sustainability. Use of materials with low embodied carbon and minimum construction waste is a viable response to avert the looming danger of climate change, says Waldman. As of now, 50% of New Zealand’s total waste is attributed to the construction sector, according to Procore’s “2024 ANZ construction forecast report”. Raw Earth or soil-based materials such as clay and cob could present a sustainable alternative, and in a recent study on the realisation of 3D printing technology, Graziella Bernardo represents Bioclimatic architecture as “…the response of modern thinking to climate change”. Furthermore, rapidly growing digital construction technologies such as 3D printing create greater opportunities in terms of design complexity and personal customisation for these readily available materials on small and large-scale fronts. 

I am Dr Don Samarasinghe, a recipient of the 2023 Construction Innovation & Quality Scholarship, dedicating my research efforts to enhancing sustainability by exploring the potential of using raw earth with 3D printing in New Zealand’s construction industry.

I had planned my project by dividing it into four stages: (1) Exploring the current state of knowledge; (2) Investigating existing techniques and materials; (3) Developing a VR training tool (EcoPrint VR); and (4) Evaluating the efficacy of EcoPrint VR. So far, I have collected and analysed the data (peer-reviewed research articles, conference publications, and project reports on materials, technologies, and skillsets) and explored the primary themes and research gaps. 

After conducting a thorough literature review, it was discovered that raw earth-based 3D printing presents numerous benefits for the construction sector in New Zealand. These advantages include robustness, ease of printing, resource efficiency, minimal toxicity, circularity, and positive environmental impact.

(Origin: Massa Lombarda Italy). Image Courtesy: WASP

Figure 1: TECLA (derived from Technology and Clay) first Raw Earth 3D printed house model built by MC A and WASP

The most recent feat in that regard is presented by WASP, a 3D printing company, with the zero-carbon house, Gaia, using new Crane WASP technology (Table 1). 

In light of these advancements, I explored the potential of integrating 3D printing technology using soil (raw earth) within New Zealand. My project specifically focused on assessing the impact of implementing 3D earth printing technology on building structures and carbon emissions. The findings highlighted the capacity of this technology to align with global trends and opportunities within New Zealand. The construction industry has been slow to embrace productivity through innovation. I addressed challenges related to productivity, circularity, and efficiency within the construction sector by proposing 3D Earth printing. It became evident that there exists a significant gap in terms of research and development within academia (see Fig 2), as well as awareness among construction professionals in New Zealand. 

Figure 2: Countries with the number of publications on raw earth research

Over a 10-year period (2011-2022), I combed through research records and archives to understand the global development of this technology and uncover potential opportunities for New Zealand. As part of a systematic literature review, using the thematic data analysis method, I screened over 400 records and conducted an in-depth analysis of the most relevant ones. Scopus scientific research database navigated through the preliminary screening of the published records. From 2011 to 2023, research on 3D printing through earthen materials has shown significant growth, as evidenced by the available data (Fig 3).

Figure 3: Research trends on 3D printing through raw earth

Moreover, the analysis of the major articles revealed materials as the most common theme (37 articles), followed by technology (34 articles) and skillset (10 articles). Fig 4 further visualises the distribution of these themes and provides insights into their respective sub-themes.

Nearly half of the analysed research data (about 45-50%) revealed that Cob (composed of 28-32% aggregates, 35-40% straw, 20-30% water, and 7-8% clay) is the most used raw earth material, followed by the clay. One study conducted by Chen identified the use of calcined clay and limestone powder as a composite printable material as a promising approach to reduce the carbon footprint and energy consumption.

Figure 4: Themes of the research articles

From the sun-baked sands of Egypt to the fertile fields of Peru, nations around the globe are transforming their soil into sustainable building blocks! Cob, Kankara clay, and X-Salt rise from the earth in Nigeria, Spain, and beyond, proving that innovation thrives where nature meets necessity. Furthermore, new recipe materials are underway with different combinations of soil-based materials (Fig 5).

Source: Grace Schleck and Lola Ben-Alon (2024)

Figure 5: Compositions of different natural materials used in raw earth-based methods

Generally, 3D printing process begins from product idea to 2D image generation and later transforms into 3D CAD model, which undergoes from facet modelling and slicing process to sliced contour data processing. The sliced contour data manoeuvred through gantry robots to a finished project, according to recently published standards ISO/ASTM 52950 (2023). Most of the research data available on 3D printing identified cementitious materials as the most abundantly used, however they contribute significantly toward greenhouse gas emissions and global warming, reported in a blog by David Shultz. Among different categories of 3D printing, widely used extrusion printing has been utilised thus far in most of the raw earth construction applications and recently a research article has developed a methodological framework for 3D clay extrusion system, as the (Fig 6).

Source: O Kontovourkis, G Tryfonos (2018)

Figure 6: Block diagram for the clay-based extrusion 3D printing

Globally, there have been several completed projects, one of which is the TECLA house built under the collaboration of WASP and MC A (Fig 1). The director of the Natural materials lab Lola-Ben Alon in Columbia University have reported better survivability and thermal comfort in earth based residential dwellings for all six different sample climatic zones. This study has strengthened the idea that widespread use of locally available soil in other countries can inspire New Zealand to explore her own avenues like Basaltic clay mined at the Matauri bay clay pit. The country has yet to fully capitalise on the potential of 3D printing in earth construction. 

Despite the promising results, several questions remain unanswered at present. Additional research is needed to better investigate long term durability and performance of 3D printed earth structures. Technical and structural properties of raw earth materials have limited information available in the literature. In future research, it is possible to examine optimal earth mix designs and suitable 3D printing techniques (Fused deposition modelling, Contour crafting etc).

Source: Grace Schleck and Lola Ben-Alon (2024)

Figure 7: A 540m² house covered with cob plaster and cordwood by Down to Earth Design

Accelerating the use of raw earth-based 3D printing is still in a nascent stage, however the conception is not that up to the minute because Earth Building Association of New Zealand (EBANZ) has already developed the standards for Earth based buildings  in 1998. EBANZ has recently responded to the Christchurch earthquakes by revising these standards in 2020 (Accessible at “NZ 4298:2020”). In New Zealand, project Lithos is an exciting opportunity leveraging upon the concept of “building in partnership with land” to encourage the construction industry stakeholders – explore and expand the path of sustainable buildings through 3D earth printing.

New Zealand has an opportunity to decarbonise construction and achieve Net Zero 2050 goals by introducing environmentally friendly, cost-effective and circularity based raw earth assisted 3D printing technology to meet the Net Zero 2050 goals, one of the pioneers of 3D printing, Behrokh Khoshnevis, rightly concluded in a TEDx talk.

In conclusion, the exploration of raw-earth 3D printing technology for New Zealand’s construction industry holds significant promise for achieving sustainability goals. Utilising materials such as cob and clay, with compositions tailored to minimise embodied carbon, offers a viable solution to mitigate climate change risks. The adoption of 3D printing technology, particularly extrusion printing, presents opportunities for design complexity and customisation while reducing construction waste. Despite progress, further research is necessary to address long-term durability and performance concerns. Initiatives like project Lithos, alongside standards set by EBANZ, signify New Zealand’s commitment to advancing sustainable construction practices. By embracing environmentally friendly, cost-effective, and circularity-based approaches, such as raw-earth assisted 3D printing, New Zealand can accelerate progress towards Net Zero 2050 goals while fostering innovation in the construction sector.