Cirmap - CIrcular economy via customisable furniture with Recycled MAterials for public Places

Abstract of the CIRMAP Project Cirmap will provide a new Mixture Proportioning Method (MPM) for the design of 3DP mortars with RFA and a new Design Methodology for Customized Shapes (DMCS). A new Master Control Command (MCC) for concrete 3DP will be implemented for the equipment of 3DP machines, and an integrated mobile 3D printing unit will be developed for onsite 3D printing of UMG furniture. A Cirmap-network will also be created for lobby and dissemination, leading to a new market for the reuse of RFA. 5 Local Public Authorities in North West Europe will provide public places that will be equipped with 3DP customized furniture. Project objectives: CIRMAP aims at finding new opportunities for the valorisation of Recycled Concrete Fine Aggregate through 3D printing of customized shapes. P Total budget : € 6.98 Million EU funding : € 4.19 Million Duration: 36 months (April 2020 – March 2023)

The first pilot scale 3D printing, within the scope of Interreg NWE CIRMAP, was successfully achieved in May 2021 at IMT Lille Douai (France)! This first 3D printing campaign was jointly led by two CIRMAP partners: ARMINES and Université d’Orléans. The cementitious ink used for printing was developed in the laboratory and contains 100% recycled sand coming from Belgium. The printed shape consisted of a 28 cm height square, and shows the good printability of the ink, as well as the good surface aspect of the mortar at the fresh state and at the hardened state. These promising results will allow to print more complex shapes in the future, suitable for urban, memorial and garden furniture uses.

The second pilot scale 3D printing, within the scope of Interreg NWE CIRMAP, was successfully achieved in June 2021 at IMT Lille Douai (France)! This second 3D printing campaign was jointly led by two project partners: ARMINES and ULiège. The cementitious ink used for printing was developed in the laboratory and contains 100% recycled sand coming from Belgium. The pre-saturation conditions of the recycled sand were changed and the blending sequence used was simplified in comparison to the first 3D printing campaign led in May 2021. The printed shapes consisted of a 34 layers height cylinder and a sinuous shape, which will be cut to obtain mortar specimens. These specimens will be used to perform durability and mechanical assessments. These results show that a simplified mortar fabrication protocol still allows to print complex shapes which will be adapted for urban, memorial and garden furniture uses.

In October 2021, CIRMAP carried out a third pilot-scale 3D printing session at ARMINES/IMT Nord Europe (France) in the scope of Interreg NWE CIRMAP. The operation was a success! This third 3D printing campaign was jointly led by two project partners: ARMINES/IMT Nord Europe and UOrléans. For this session, a cementitious ink was formulated using 100% recycled sand from Germany. The printed shape consisted of a 40-layer height cylinder. These results show that the formulations developed in the laboratory allow the printing of various shapes which will be adapted to urban, memorial and garden furniture uses.

In March 2022, CIRMAP carried out a fourth pilot-scale 3D printing session at the ARMINES/IMT Nord Europe laboratory (France) in the framework of Interreg NWE CIRMAP. For this session, the cementitious ink used was formulated with 100% German recycled sand, and successfully printed the last letter of "IMT". This impression allows to close the printing of the 3 letters that compose "IMT" Nord Europe, laboratory where different formulations have been developed for the CIRMAP project.

In April 2022, CIRMAP carried out a pilot-scale 3D printing session at the ARMINES/IMT Nord Europe laboratory (France) in the framework of Interreg NWE CIRMAP. For this session, the cementitious ink used was formulated with 100% Dutch recycled sand, and successfully printed the letter of "A" of "CIRMAP".

In June 2022, CIRMAP carried out a pilot-scale 3D printing session at the ARMINES/IMT Nord Europe laboratory (France) in the framework of Interreg NWE CIRMAP. For this session, the cementitious ink used was formulated with 100% French recycled sand, and successfully printed the letter "C" of "CIRMAP".

In July 2022, CIRMAP carried out a pilot-scale 3D printing session at the ARMINES/IMT Nord Europe laboratory (Douai, France) in the framework of Interreg NWE CIRMAP. For this session, the cementitious ink used was formulated with a german recycled sand, HEBERGER, and successfully printed frames intended for mechanical testing by the german partner « TU Kaiserslautern ».

After several months of research and experimentation conducted by a European team of academics and industrialists, including Neo-Eco, the results are finally here. With all the recycled sands of each European country involved in the project, we have succeeded in : 🔸Substitute 100% of the raw materials by recycled sands in the formulations 🔸Controlling the water absorption of these sands 🔸3D printing this new ecological concrete. 3D printing tests have been carried out and are a success. We can thus imagine many applications such as: urban furniture, coverings, products of original design shape, prefabricated products, assembly products, insulations, customization products (for example in gardening), etc... If you are interested in specific formulations or the creation of 3D printed cementitious eco-products, please contact Sophie Heymans, our R&D manager, member of the CIRMAP team (sheymans@neo-eco.fr). This project is supported by the Interreg North-West Europe program, which promotes transnational cooperation between private and public actors, in order to develop ecological and economic solutions with strong ambitions in terms of innovation, sustainability and cohesion.

Demolition for recycling construction waste

In Wallonia, production of inert demolition waste is around 7 million tonnes per year (Plan Wallon Déchets - Ressource, 2018), which represents approximately 2 tonnes of waste per inhabitant per year! In order to be able to recycle this waste, it is important to act at the source, as soon as buildings are demolished.

The first step is to draw up an inventory of different waste streams to be disposed of separately. The inventory consists of listing all waste released during demolition as well as their quantity. Currently, the production of an inventory is not a legal obligation, but it remains an essential tool that allows better waste planning management: number of containers, treatment channels, distance to go for the evacuation, …

Inventory helps to identify different flows:

- Inert waste: concrete, bricks and tiles, ceramics and tiles, untarred asphalt. Today, this waste can no longer be landfilled and must be recovered. A part can be reused and the rest will be recycled in the form of aggregates. Recycled aggregates have multiple applications: earthworks, foundations, sub-foundations and new concrete.

- Non-hazardous non-inert waste: wood, metals, glass, insulation, plastics, plaster, paper, textiles. These materials can also be recycled if properly sorted. Their sorting is unfortunately often limited to high-value materials such as metals.

- Hazardous waste: asbestos, tar, heavy metals, etc. They require decontamination of the building before demolition and they are disposed of separately and stored under specific conditions.

Then comes actual demolition. There are different methods of demolition which are chosen according to location, environment (urban or rural), volume and composition of building to be demolished:

• Manual demolition: building is knocked down starting with its upper parts. The demolition is done gradually, from top to bottom. This method is used when objective is to reduce building height without demolishing the foundations, or if one seeks to make a partial restoration rather than a reconstruction.
• Mechanical demolition: this is done using a hydraulic mechanical shovel and is ideal for demolishing load-bearing concrete walls. The bucket acts as a demolisher but can also load skip with the waste produced.
• Demolition with explosives: it is not often practiced and requires specific know-how.

Once the building is demolished, it is necessary to sort different flows identified during inventory. Sorting can be manual or via sort lines.

After sorting, the waste is evacuated to recycling centers where it is treated and marketed as secondary resources.

What is a recycling centre ?

A recycling center generally offers several services : recovery and consolidation of excavated soil, inert construction waste recycling and recycled products sale.

When we speak of inert waste, we mean any waste that does not decompose, does not burn and does not produce any physical or chemical reaction. When we talk about construction and demolition waste, inert waste includes brick, tiles, tiles, glass, earth and stones, bituminous and concrete.

Inert waste recycling is an obligation in the Walloon Region. Waste is sorted directly on site and then transported to approved recycling centres. They can come from buildings deconstruction, road surfaces, etc.

Inert waste treatment includes several stages that begin directly on site and continue in the recycling center:

Selective sorting of waste

A first selective sorting of waste is done directly on site. This sorting is extremely important for the smooth running of the following steps. Indeed, it allows more efficient recycling and the use of the recycled product in higher performance applications. It allows, for example, the use of concrete waste as aggregates for new concrete prdocution where unsorted waste will be used as backfill material.

Reception, control and storage in a recycling center

Upon arrival at the recycling centre, waste is weighed and identified. Non-inert and hazardous waste such as hydrocarbons containing tar or asbestos are detected beforehand and prohibited from entering. For others, they are stored on different piles depending on their origin, hence the importance of sorting on site! There are generally 3 main categories : mixed, concrete and hydrocarbon. These categories are generally dealt with separately.

• Concrete: Concrete waste comes from deconstruction of buildings or civil engineering infrastructure (concrete or reinforced concrete).
• Mixed : Mixed waste comes from buildings construction/renovation/deconstruction (bricks/blocks/tiles).
• Hydrocarbon: Hydrocarbon waste comes from civil engineering infrastructure deconstruction (road surfaces, etc.), car parks demolition, etc.

Treatment and sorting of undesirables

Waste is then transformed into secondary material by passing different steps :

• Pre-scalping is a preliminary operation whose purpose is to eliminate soil potentially present in raw waste. It is carried out using a sieve:
• Crushing consists of grinding materials to reduce their dimensions.
• Screening is the operation of sorting different elements produced during crushing according to their dimensions. It therefore makes it possible to establish different categories of materials according to their application: sand, gravel for concrete, gravel for backfill.

During these stages, unwanted waste (wood, paper, green waste, metals, etc.) is removed using different methods: manual sorting tables, blowers/suction, electromagnets, flotation/washing.

Quality and environmental control

Recycled aggregates production is governed by a quality management system (FPC) which certifies their compliance with European product standards. Aggregates are subject to regular sampling for quality control.

As part of the new legislation "Exit from waste status", recycled aggregates placed on the market as a product must be CE2+ certified. CE mark indicates that the product meets European requirements for safety, health and environmental protection. All natural or recycled aggregates placed on the market in applications covered by a harmonized standard must bear this marking.

Technical characteristics and marketing

Once produced, recycled aggregates are stored by type (mixed, concrete, hydrocarbon) and by grain size. They will be marketed for applications according to their characteristics and grain sizes.

In May 2023, CIRMAP carried out a pilot-scale 3D printing session at the ARMINES/IMT Nord Europe laboratory (Douai, France) in the framework of Interreg NWE CIRMAP. For this session, the cementitious ink used was formulated with nickbrookes, an English recycled sand, and successfully printed the last letter from CIRMAP «P». We now have all the CIRMAP letters printed with different recycled sand each.

In May 2023, CIRMAP carried out a pilot-scale 3D preliminary printing session at ENSAPL (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the corresponding recycled sands, the German (Left picture) and French (Right picture) urban furniture prototypes were successfully printed.

On the 26th and 27th of June 2023, CIRMAP carried out a pilot-scale 3D printing session at Polytech Lille (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the Dutch recycled sand "Cirwin", the seven different parts of the furniture prototype were successfully printed.

On 22/06/2023, CIRMAP carried out a pilot-scale 3D printing session at Polytech Lille (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the german recycled sand "Heberger", five urban furniture prototypes were successfully printed.

On 19-20-23/06/2023, CIRMAP carried out a pilot-scale 3D printing session at Polytech Lille (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the french recycled sand "Helfaut", three of the french urban furniture prototypes were successfully printed.

On the 29th and 30th of June 2023, CIRMAP carried out a pilot-scale 3D printing session at Polytech Lille (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the belgian recycled sand "Tradecowall", the urban furniture prototype composed of 11 different pieces was successfully printed.

On the 11th – 12th of July 2023, ENSAPL, in collaboration with ARMINES/IMT Nord Europe, carried out a pilot-scale printing session at ENSAPL (Villeneuve-D’ascq, France) in the framework of the 3D Build 2023 summer school. For this session and with the cementitious ink containing the recycled french sand, different challenging prototypes were successfully printed

On the 14th of September 2023, CIRMAP carried out a pilot-scale 3D printing session at ENSAPL Lille (Villeneuve-D’ascq, France) in the framework of Interreg NWE CIRMAP. For this session and with the cementitious ink containing the Helfaut french RFA, Vicat cement and Chryso superplasticizer, a 1m-prototype was successfully printed.

Upscalled printing with 100% recycled agregates - june 2023

Workflow Implementation for Automatic Detection of Filament Deviation in 3D Robotic Printing Process

On October 16, 2023, the inauguration of the urban furniture installed on the square in front of the Douai Conservatory took place in the presence of the Mayor of Douai Frédéric CHEREAU and the director of IMT Nord Europe Alain SCHMITT. These urban furniture were 3D printed with cement ink based on 100% recycled concrete sand as part of the Interreg North West Europe CIRMAP project led by Armines and IMT Nord Europe. In homage to the conductor Georges PRETRE, these urban furniture were designed from cylinders distorted by musical melodies. This achievement was done in partnership with the Lille School of Architecture (ENSAPL) and Polytech Lille and Orléans.

The CIRMAP project in video. summary of 3D printing actions

From september 5th to 11th and from september 28th to october 2nd, CIRMAP project held 2 workshops with architecture students from universities of Lille, Kaisersleutern and Liège. The aim of those workshops was to experiment 3D printing with 100% fine aggregates in order to test shapes faisability and printing mortars formulation at a small-scale. CIRMAP objective is to make cimentitious inks in order to provide 5 public places with pilot 3D printed customized furniture. Five partner countries will receive these furnitures printed with their own recycled sand. These worskhops were also the opportunity to test recycled sand from several countries. During the first workshop, students worked first on concepts/ideas and design. They printed 3D small-scale plastic prototypes. Then they had one day of printing tests. The first indicator to verify was the imprimability of shapes. The second indicator to verify was the mortar formulations by adjusting the amount of water. The use of a climatic chamber allows to test printing performance depending on temperature and humidity. In total about 7-8 shapes were tested. This workshop demonstrated promising results but difficulties still remain when the height or the eccentricity of shapes increases. These problems can be solved by changing the printing flow or the nozzle speed. During the second workshop, the students chose to develop concepts based on metaphorical ideas: a mobius strip and organic growth clusters. Much of their effort was focused on developing clear computational logics that would allow their concepts to be implemented in a variety of locations. During their 2 printing sessions at Polytech Lille and the CSTC, they explored the limits of what could be done in terms of overlapping during the extrusion process as well as gain a better idea of what could be feasible for local slopes in their geometry and the effects/parameters/possibilities of nonplanar printing.

ENSAPL and Polytech Lille, in the framework of the CIRMAP project, organized a Workshop from 1 to 3 December 2021 in Lille, in collaboration with ARMINES/IMT Nord Europe and University of Liège. The purpose was to design and manufacture the first prototypes of urban furniture using 3D printing technology, with recycled materials. The shapes were printed using a cementitious ink formulation that was previously tested at the ARMINES/IMT Nord Europe research laboratory. Some of these prototypes will subsequently be used to produce the final furniture which will be installed in the place in front of the Douai Conservatory. To commemorate a great orchestra conductor: Georges PRÊTRE. The optimisation and design of the shapes - developed by the students of ENSAPL - will reduce the overall quantity of mortar and the use of local recycled sand will reduce the depletion of natural resources and avoid landfill. The workshop showed the successful collaboration between the different partners of CIRMAP!

CIRMAP designed and implemented a new Mixture Proportioning Methodology (MPM) for the formulation of 3D printing mortars containing Recycled Fine Aggregates (RFA), starting from the formulation of an existing 3DP mortar made with natural sand (NS) and complying with the specifications of 3D printing. This methodology is based on the following steps: Step 1: fast and accurate assessment of the Water Absorption coefficient (WA) of RFA and computation of the oven-dried particle density (or envelope density) rrd Step 2: substitution of the envelope volume of NS by the same envelope volume of RFA Step 3: slight adjustment of the High Range Water Reducing Admixture (HRWA) amount to get the same initial workability in order to account for small differences of intrinsic viscosity and packing density of RFA versus NS. This methodology and its validation have been described in details in the following publication : Materials and Structures (2023) 56:165 (https://doi.org/10.1617/s11527-023-02251-4) The methodology was tested on various RFA from different origins in North West Europe. It allowed to produce 3D printing mortars where 100% of the natural sand was replaced by RFA without affecting significantly neither the printability nor the mechanical performance of the mortar. The figure below shows for example the compressive strengths obtained after 2, 7,and 28 days on 3DP mortars made with natural sand (NSM) and two recycled sands used in the project (RSM1 and RSM2).

The master control command (MCC) developed and implemented in the CIRMAP project for 3D printing of furniture with recycled materials serves several crucial roles in optimizing and enhancing the 3D printing process. The MCC allows for real-time adaptation of printing parameters based on environmental conditions (e.g., temperature, humidity) and material behavior. This adaptability ensures that the 3D printer can adjust its settings dynamically to maintain optimal printing conditions. By continuously monitoring and adjusting printing parameters, the control system contributes to maintaining a high level of print quality. It helps preventing issues such as warping, layer separation, or inconsistent material deposition that can arise from variations in environmental conditions. The control system can optimize printing parameters based on the specific properties of recycled materials being used. Adaptive control enhances the robustness of the 3D printing process. It allows the system to operate effectively in uncontrolled or changing environments, reducing the likelihood of print failures or defects. By optimizing printing parameters, the control system contributes to resource conservation. It ensures that the 3D printer operates with minimal waste, utilizing recycled materials efficiently and reducing the need for reprints. The MCC allows for customization of printing parameters based on the specific requirements of each printing job. This adaptability is particularly important when producing custom-designed furniture with recycled materials with diverse shapes and structures. Consistency in printing conditions leads to consistent output. Finally, the MCC helps maintaining a standardized level of quality across various print jobs, contributing to the reliability of the 3D printing process.

The mobile unit developed in the framework of the CIRMAP project and dedicated to 3D additive manufacturing for the production of public furniture using recycled materials offers several advantages. First, it allows for on-site manufacturing of public furniture, reducing the need for transportation and logistics. This is particularly beneficial for urban projects where transportation costs and environmental impact are concerned. The 3D printing technology enables customization of furniture designs to suit specific public spaces. The mobile unit can adapt to different locations, responding to the unique needs and aesthetics of various communities. By using recycled materials as feedstock, the mobile unit promotes sustainability and contributes to environmental conservation. It aligns with the principles of the circular economy by repurposing waste materials for functional and aesthetically pleasing furniture. The presence of a mobile unit in a community can facilitate engagement and collaboration. The mobility of the unit allows for rapid prototyping and iteration of designs. This agility is valuable for testing and refining furniture concepts based on real-world feedback, ensuring optimal functionality and aesthetics. On-site production reduces transportation costs and associated expenses. The use of recycled materials may also contribute to cost savings compared to traditional manufacturing methods that rely on new raw materials. The mobile unit can serve as an educational tool, providing opportunities for academia, community groups, and individuals to learn about 3D printing technology, recycling practices, and sustainable design. Finally, the mobility of the unit enables it to respond quickly to local needs and emerging trends. It can be deployed to areas with specific requirements, such as disaster-stricken regions or areas undergoing rapid urban development.

The fundamental essence of the Design Methodology for Customized Shapes (DMCS) within the INTERREG NORTH West Europe project 'CIRMAP' lies in the fusion of computational design with advanced robotic technology. Engaging esteemed academic institutions—ENSAP Lille, U-Liège, MMU (Manchester Metropolitan University), and TU Kaiserslautern—our collective aim was to push the boundaries of large-scale additive manufacturing by orchestrating a transdisciplinary approach. At the heart of DMCS is the application of computational design methodologies to generate intricate and complex shapes conducive to 3D printing. The primary focus revolves around understanding the intrinsic relationship between form, material, and machinery as a cohesive global framework. This interplay between form, material study, geometry, morphology, and design aligns cohesively within the realm of concrete 3D printing, bridging diverse disciplines and expertise. This multidisciplinary approach harmonizes the expertise in material science, form exploration encompassing geometry and morphology, and the utilization of cutting-edge robotics. The integration of these elements within DMCS signifies a concerted effort to redefine construction methodologies and advance the capabilities of additive manufacturing. Through international workshops and collaborative engagements, students from diverse backgrounds were immersed in a collaborative environment aimed at exploring the nuanced relationships between form, material, and machinery. This interdisciplinary dialogue culminated in successful 3D printing initiatives, illustrating the seamless convergence of computational design, material intricacies, and robotic precision. DMCS, as a pioneering initiative, represents a unified effort to harness the potential of computational design in tandem with robotic technology, fostering a paradigm shift in construction practices and bolstering the broader aspirations of the CIRMAP project.

On October 16, 2023, the inauguration of the urban furniture installed on the square in front of the Douai Conservatory took place in the presence of the Mayor of Douai Frédéric CHEREAU and the director of IMT Nord Europe Alain SCHMITT. These urban furniture were 3D printed with cement ink based on 100% recycled concrete sand as part of the Interreg North West Europe CIRMAP project led by ARMINES and IMT Nord Europe. In homage to the conductor Georges PRETRE, these urban furniture were designed from cylinders distorted by musical melodies. This achievement was done in partnership with the Lille School of Architecture (ENSAPL) and Polytech Lille and Orléans.

On November 06, 2023, the inauguration of the urban furniture installed the Pirmasens University Campus near the “Marie-Curie-Straße” took place. The event was organised by Pirmasens and supported by RPTU. Mayor Michael Maas from Pirmasens and Professor Christian Glock from RPTU introduced the pilot and the Cirmap project to the press.

The UK urban furniture designs were printed by Manchester Metropolitan University and designed by Sam Merrick, a product design student at the university. Sam was inspired by differential growth and parametric modelling to create bespoke shapes. They are installed in Rochdale Cemetery (photos 1, 2 & 3 below), Greater Manchester and form part of a wider landscaping project that will be appreciated by visitors to the cemetery. Prototype prints are also on display in Material Source Studio, Manchester, for the CIRMAP exhibition ‘Full Circle Concrete (photo ). An inauguration event will be hosted at Material Source Studio 24th January 2024.

Thierry Permentier, Head of the Urban Waste Management Department of the City of Almere, unveiled two new benches on the 29th of November 2023. These benches were made, because Almere is participating in the CIRMAP project, supported by Interreg North-West Europe. The bottom of the benches are made of recycled sand (RFA) from the local waste recycling company Cirwinn. A lot of recycled sand coming from construction waste does not meet the requirements for using it in the housing sector, road and hydraulic engineering and therefore ends up in landfills. In CIRMAP the project partners did research and some testing in order to find different applications for the recycled sand (RFA) and to create 3Dprinted concrete material for that. The concrete benches’ elements were printed in Lille by the Polytechnical University. The sea boards were made from recycled single use plastic by the Green Plastic factory, supported by another Interreg NWE project (Transform CE) in which the City of Almere participated. Mr. Thierry Permentier, Head of the Urban Waste Management Department of the City of Almere was very pleased with the result of the project, the new benches at the entrance of the Urban Waste Department office. It demonstrates the ambitions of the City of Almere to give waste materials a new life in an innovative way. As a result, we now have two completely recycled benches in front of the office of the Urban Waste Management Department on the Steiger. What was normally considered as waste has now been used to make furniture for public spaces.