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Volume 6 2018

Dutch Design Week 2018 3D-knitted shells Alkali Activated Material Re-printing architectural heritage Optimal reuse of the fine fraction of recycled concrete



CONTENT Innovatieve Materialen About is een vaktijdschrift gericht op de civieltechnische Innovatieve Materialen sector en bouw. Het bericht over ontwik(Innovative Materials) is a digital, kelingen op het gebied van duurzame, inindependent magazine novatieve materialen en/of deabout toepassing material innovation in the fields of daarvan in bijzondere constructies.

engineering, construction (buildings, infrastructure and industrial) and Innovatieve Materialen is een uitgave van industrial design. Civiele Techniek, onafhankelijk vaktijdschrift voor civieltechnisch ingenieurs werkzaam in de grond-, weg- en waterA digital subscribtion in 2018 bouw en verkeerstechniek.

(6 editions) costs € 39,50 (excl. VAT) of KIVI-leden and DeMembers redactie staat open voor bijdragen students: van vakgenoten. U kunt daartoe contact € 25,- (excl. VAT) opnemen met de redactie.


SJP Uitgevers


Postbus 861 SJP Uitgevers 4200 AW Gorinchem tel. +31 183 66 08 08 Postbus 861 info@innovatievematerialen.nl

4200 AW Gorinchem tel. (0183) 66 08 08 e-mail: info@innovatievematerialen.nl Editor www.innovatievematerialen.nl

Gerard van Nifterik

Redactie:& Advertizing sponsoring Bureau Schoonebeek vof

Drs. Petra Schoonebeek Hoofdredactie: Gerard van Nifterik

Innovative Materials platform: Advertenties Drs.Veer, Petraprof. Schoonebeek Dr. ir. Fred Ir. Rob Nijsse (Glass & Transparency Research e-mail: Group, ps@innovatievematerialen.nl TU Delft), dr. Bert van Haastrecht (M2I), prof. Wim Poelman, dr. Ton Een digitaal abonnement in 2016 Hurkmans (MaterialDesign), (6 uitgaven) kost € 25,00 (excl. BTW) prof.dr.ir. Jos Brouwers, (Department of the Built Environment, Section Building Zie ook: www.innovatievematerialen.nl Physics and Services TU Eindhoven), prof.dr.ir. Jilt Sietsma, (4TU.HTM/ Niets uit deze uitgaveand magMaterials worden Mechanical, Maritime verveelvuldigd en of openbaar Engineering (3mE), worden door middel van herdruk, fotokopie, miprof.dr. Pim Groen, (SMART crofilm of op welke wijze dan ook, zonder Materials Aerospace Engineering voorafgaande schriftelijke toestemming (AE) TU van Delft/Holst Centre, de uitgever. TNO), Kris Binon (Flam3D), Guido Verhoeven (Bond voor Materialenkennis/SIM Flanders).

1 News 10 Make it Matter 12 Dutch Design Week 2018 22 3D-knitted shells save on construction materials and time

With just the press of a button, ETH researchers knit a textile that serves as the primary shaping element for curved concrete shells. Now they have used the new technology - KnitCrete - to create a five-tonne concrete structure for an exhibition in Mexico City. The formwork is made of a knitted textile: KnitCandela.

26 Mineral waste, a needed source material for the production of future prospective building materials

Alkali Activated Material technologies prove that the overall increasing quantity of mineral waste around as an output of growing population, can stand for a unique position as source material for concrete materials.

30 Re-printing architectural heritage

Additive Manufacturing (3D printing) technology has become a global phenomenon. In the domain of heritage, 3D printing is seen as a time and cost-efficient method for restoring vulnerable architectural structures. The technology can also provide an opportunity to reproduce missing or destroyed cultural heritage, in the cases of conflicts or environmental threats. The 4TU-project ‘Re-printing architectural heritage’ has taken the Hippolytuskerk in the Dutch village of Middelstum, as a case study to explore the limits of the existing technology, and to investigate the potential of 3D printing cultural heritage. Architectural historians, modelling experts, and industrial scientists from the universities of Delft and Eindhoven have engaged with aspects of 3D printing, to reproduce a selected part of the 15th century church. This experimental project has tested available technologies to reproduce a mural on a section of one of the church’s vault with maximum possible fidelity to material, colours and local microstructures. The project shows challenges and opportunities of today’s technology for 3D printing in heritage.

34 Sustainable materials for smart cities

As the speed of innovation is increasing and the earth’s population is growing, the past century has seen a 34-fold increase in materials consumption, resulting in large waste streams and associated CO2 emissions. It is widely recognized that this linear ‘take, make, dispose’ model cannot be maintained. A solution for this challenge is to keep structures and devices in use for as long as possible. This should be done with a minimum amount of materials preferably from waste streams, and should be economical and safe.

35 Optimal reuse of the fine fraction of recycled concrete

Recently a new research project has started focusing on the optimal re-use of the fine fraction of concrete in new concrete with TNO, M2i, TU Delft, RWS, Twee R Recycling, Cementbouw Recycling, AVG en BRBS Recycling The project is supported by the Dutch Topsector High Tech Systems & Materials (HTSM).

38 Understanding Structure Formation in Hierarchical Hybrid Materials using Cryogenic Electron Tomography and Liquid Phase Electron Microscopy

Cover: Chaise longue with with variable stiffness by Henriette Bier and Arwin Hidding, pag. 15


GrasGoed: insulation mats based on grass The Dutch company NewFoss (biobased products & technologies) and Natuurmonumenten have developed insulation mats based on grass: GrasGoed. Natuurmonumenten supplies cuttings that are released during the management of their nature reserves. NewFoss washes impurities from the clippings. The clippings are then cut with super sharp blades into pieces of 1 to 5 cm. NewFoss uses a biological process to extract valuable substances from the grass, such as sugars, proteins and amino acids. A part is converted into energy, so that the processing process in the NewFoss plant can take place in an energy-neutral way. The fibers that remain are used for the insulation mats. The NewFoss bio refinery installation in Uden has a yearly production capacity of 40,000 tons of biomass. The output amounts to 11,000 tons of biobased lignocellulosic fibre (dry matter).

According to the parties involved, these grass clipping mats are a sustainable alternative to existing mineral insulation mats. The insulating boards consist of 75 % grass fibers, the acoustic panels even 90 %. The plates have a lambda insulation value of 0.04.

Biobased mats still play a minor role in the insulation market. Some 95 % insulation material is still mineral products such as glass or rock wool, the biobased variants cover the remaining 5 %. The development of the insulation mats was supported by the Interreg Border

The NewFoss process for biomass waste flow processing entails four steps: (1) Washing of the biomass waste flow to rid it of impurities that are heavier than water, such as sand and stones (2) Biologically opening the cell walls (make them permeable) which releases the intracellular components (3) Rinsing of the opened cells to extract the liquids (4) Further processing of the biomass to match the client’s specific wish

Project, which receives support from the European Regional Development Fund. The province of Antwerp and the province of Noord-Brabant also gave financial support to the project. www.grasgoed.eu>




‘3D-printed bridge alternative to traditional bridge’ Engineering and consultancy firm Antea Group, together with Cybe Construction, has started a pilot to make 3D-printed concrete bridges a serious alternative to traditional bridges. According to the parties involved, the 3D printing technique makes it possible to print bridges within one day, which currently stands for four weeks with a traditional construction method. In addition, 3D printing ensures optimal material use and makes new architectural forms possible. The aim of the pilot is to design a 3D printed bridge that is structurally safe and can compete economically with a traditional bridge. Initially, it concerns the design and printing of a seven-meter-long concrete footbridge. Because there are no guidelines and standards for printed concrete, the design will have to be verified by means of ‘Design by testing’. Meanwhile The pedestrian bridge has been printed and is being tested and researched in Oss. More at Antea Group (Dutch)>




Popcorn laminate

Photo’s: Moira Burnett

The idea is not entirely new, because Professor Alireza Kharazipour of the University of Göttingen has been working for years on a so called ‘Popcorn-Platte’, but now he and his research team say to have actually succeeded in developing particularly light sandwich panels with a core of expanded corn kernels.

a mixture of expanded maize with wood fibres (a composite, not a laminate). It was presented at the BAU 2011 trade fair in Munich and is marketed by Pfleiderer AG under the name BalanceBoard. The density of BalanceBoard is 500 kg/m3; the new laminate material would

be much lighter with 300 - 400 kg/m3. The chipboard chip density is 650 kg/m3. Baulinks> The research report online (pdf, German)>

During the research project, the researchers looked at two different methods: a single-step process in which expanded maize in the core, and wood chips and wood fibers, were glued into the top layer. And a two-step process, in which the popcorn core was first made, after which the surface materials were applied in a second step, like thin plywood, thin chipboard, aluminium or high-pressure laminate (HPL-High Pressure Laminate). Further research showed that such popcorn materials have similar properties as conventional chipboard, but are much lighter. According to Professor Kharazipour, the expanded maize also binds the formaldehyde (up to 70 °C) that is afterwards released from the glue. The emission of formaldehyde is often a problem with glued sheet materials. Previously, Kharazipour had developed another sheet like material, made from



Ecocell: building with paper IDEA-Suisse, the Schweizwerische Gesellschaft für Ideen- und Innovationsmanagement (Zurich), has awarded the thirtieth Swiss Innovation Award to Ecocell Technology AG from Uttwil, Thurgau, Switzerland. The company receives the price for the development of a building material made from recycled paper and a thin mineral, cement based coating, the patented Betonwabe. This produces a kind of honeycomb structure with a core of cardboard reinforced with cement. That is the core of a modular construction system called ‘Ecocell’. According to the manufacturer, the ecological base material has excellent construction properties because it is lighter and more durable than conventional building materials. Components can be fully


prefabricated industrially, which reduces time-consuming work on the construction site and reduces building costs by up to 50 percent. According to the company, the building material binds large amounts of CO2 and thus provides a significant greenhouse gas reduction. www.ecocell.ch www.idee-suisse.ch


Recycled Park Plastic waste is a structural problem in open waters. Via rivers a subsequent part of plastic litter enters our seas and oceans, where it becomes part of the plastic soup. Recycled Park is the proposal to retrieve plastic waste from the river the New Meuse just before it reaches the North Sea. From this plastic waste, floating platforms are constructed for a new green environment: a floating park. The proposal is an initiative of WHIM architecture and the Recycled Island Foundation in collaboration with the Rotterdam municipality, and HEBO Maritiemservice. Passive waste collectors are used to collect plastic waste from the river. With Wageningen University (WUR) the collected plastics are analysed and a process is selected to produce the floating building blocks. These hexagonal blocks are connected to a pen. For the time being the blocks have sides of two meters, but the final dimension can only be determined after the analyses of the plastics have been made and the potential

strength of the recycled material is investigated. The chosen shape of the blocks is used as a basis for further development. The building blocks are designed in such a way that not only can new life arise at the top, but new life in the water must also begin to settle at the bottom of the block.





Rock Print Pavilion A construction robot has created a pavilion using nothing more than loose stones and string. Between 4 October and 4 November 2018, researchers of ETH Zurich showed their work as part of an exhibition at the Gewerbemuseum in Winterthur, Switzerland.


The robot processes gravel and string into eleven three-metre-high, stable columns. Thirty tonnes of loose stones, 120 kilometres of string - and a construction robot: the Rock Print Pavilion was built using nothing more than these three key elements. The temporary installation at Kirchplatz, in front of the Gewerbemu-

seum in Winterthur, is a research project run by Gramazio Kohler Research, the ETH Chair of Architecture an Digital Fabrication, and is part of the so called ‘Hello, Robot. Design between Human and Machine’ exhibition. The question was: how can a structure made of loose stones and string be so

NEWS continuously calculated by the robot - this creates a stable, highly durable structure. The Rock Print Pavilion is exploring the possibilities offered by digital and robotic manufacturing. Recycling is also embedded into the project: the components can be easily dismantled and the material reused. (Photo’s: Gramazio Kohler Research/ETH Zürich)


stable that it can support the eighttonne steel roof? The phenomenon is known as ‘jamming’. The ETH research project ‘Design and Robotic Fabrication of Jammed Archi-

tectural Structures’ is focused on the robot-based assembly of simple, loose and granular base materials. The loose stones interlock together; when combined with the arrangement of string between the gravel layers - which is


Fibre Fixed: Composites in Design Composites in Design presents an extensive selection of design projects with composite material. Untill 21 April 2019 in the exhibition Fibre-Fixed is held in the Design Museum Gent, Belgium. The presentation shows an overview of what is possible when fibres are combined with a (bio)plastic, to form fibre-reinforced composite materials. Designing with composite materials takes place in the context of current worldwide challenges: global warming, ecological impact, sustainability, mobility, the ageing of population and digitisation.Curators Ignaas Verpoest (KU Leuven) and Lut Pil (LUCA School of Arts) focus on the developments of the past five years and present breakthroughs expected for the coming years. www.designmuseumgent.be>




MAKE IT MATTER MAKE IT MATTER is compiled in collaboration with MaterialDistrict (MaterialDistrict.com). In this section new, and/or interesting developments and innovative materials are highlighted.

Eoacoustic conifer panels Eoacoustic conifer panels are decorative, sound-absorbing panels made from conifer needles. The panels focus on sustainable material usage without harming the environment. The needles of felled trees, which are usually discarded as waste, are collected and turned into wall panels. The sound-absorbing fibre material is based on conifer needles and a biodegradable binder. The panels are available in various shapes and sizes, with or without patterns. More>

Extruded aluminium panels These corrugated faรงade panels are made from extruded aluminium using an EN AW 6060 alloy. This alloy has excellent extrusion properties, which has a positive effect on the visible side of the product. The surface can be anodised or treated with a powder coating. Aluminium can be 100 % recycled without being downgraded. For the faรงade panels, Norsk Hydro uses 75R, aluminium with 75% recycled content. More>

Division & Growth glass tiles Division & Growth are glass tiles with colourful patterns integrated into them. The process for these tiles is to make glass rods in various colours and designs within the hot shop using molten glass from a furnace. Once cold, these rods are cut up and fused into a flat sheet in a kiln. The tiles are usually 15 x 15 cm, but custom sizes and shapes can be made. This technique can also be used to make small tableware such as dishes and coasters or larger architectural pieces. More>



Jesmonite composite Jesmonite is a composite material made from a combination of a reactive mineral base and a pure water-based acrylic resin. It can be used to replicate the appearance and texture of any surface finish in any number of colours. The material is strong, flexible and durable, making it high impact resistant. It’s lighter than stone, glass-reinforced concrete, sand and cement products and fire-resistant. It can also mimic any texture and reproduce the effect of materials such as stone, metal, wood, leather and fabric. More>

Lithoplast Lithoplast is a new composite material by designer Shahar Livne. Lithoplast is composed of residues from industrial and anthropocenic waste streams. It is produced through geo-mimicking Metamorphism - the geological process that transforms minerals and rocks in the depths of the earth and after heating can be shaped like clay and processed by hand into sculptural functional design objects. Lithoplast was nominated for the New Material Award 2018. More>

Waste metal pigments This series of ceramic metal waste tiles from the project ‘Ignorance is Bliss’ are coloured using 100% pigment derived from industrial metal waste. Collaborating with Dutch companies, such as soil remediation and water treatment plants, designer Agne Kucerenkaite is supplied with raw waste material containing lots of metals. The metals give colour to the ceramic glaze during firing. The composition of the metal waste is the same as industrially produced colour pigments and is therefore a suitable and sustainable alternative. More>

SilicaStone SilicaStone is a material created from recycled waste glass and ceramics. This patented process allows the creation of a range of surfaces that offer new design possibilities for both interior and exterior projects. SilicaStone feels like stone and, because it is not bonded by resin, it is UV stable and will not fade or change colour over time. It is also heat and fire resistant. SilicaStone is available in 15 standard colours and in 3 standard finishes, textured, honed and glazed. More>



Dutch Design Week 2018 Every year in October, the Dutch Design Week (DDW) takes place in Eindhoven. Between 20 and 29 October the largest design event in Northern Europe presented the work of over 2600 designers. This year, 355,000 visitors from home and abroad found their way to Eindhoven, where not only presentations were facilitated throughout the city, but also exhibitions, lectures, awards, network meetings, debates and festivities. Much attention was payed to material innovations, 3D-printed materials and objects, biomaterials and circularity.



DDW: MX3D wins Design Research Award The 3D-printed steel bridge from MX3D was awarded during the Dutch Design Week, in the category Design Research. It is a steel bridge, 3D printed by robots. It will be placed center of Amsterdam, being the first 3D-printed, steel bridge in the world. This project is an initiative of the Dutch start-up MX3D and designed by Joris Laarman. The development came about with partners including Arup, Autodesk, Heijmans, ArcelorMittal and Imperial College London. ‘The form and material freedom achieved by Laarman and MX3D hint at almost unimaginable scenarios,’ the jury said.


The bridge will be placed over the canal of the Oudezijds Achterburgwal (Wallen). The project marks a breakthrough for the innovative possibilities of (large-scale) 3D printing: the introduction of this technique to a public use object increases the social awareness and integration of this technology. According to the DWW jury, the project symbolises

the speed with which this new technology and possible applications are developing. www.mx3d.com www.jorislaarman.com



Recomposed Bamboo Bamboo can, of course, be used because of its decorative qualities but Chris Kabel chose a different approach in 2016 when, at the invitation of Shanghai University, he settled down in Anji, the bamboo capital of China. Gradually, he focused his research solely on bamboo’s structural characteristics. Bamboo has a favourable ecological footprint compared with steel, aluminum or wood. It grows quickly, binds CO2 and protects the soil against erosion. Kabel is familiar too with the products made by companies like Ikea in China and sold as ‘sustainable’: cutting boards and other household items in which the bamboo fibres are cut and glued. He decided to search for a smarter way of bonding, in which the characteristics of the material are put to better use. Because although bamboo is difficult to safeguard against moisture and fungus, the long fibres that lie mainly along the outside of the stem make the material exceptionally strong. He began to experiment with these parts of the plant. The result was a series of profiles in which only the mechanically strongest parts of the bamboo are glued together, creating an extremely stiff construction material that is stronger than hardwood and almost as strong as steel. www.chriskabel.com

Multicomplex How to construct a lightweight arch with a span of 5 meters using flexible plywood sheets? The solution - using an ‘active bending’tecnique - came from Arthur van Lier Build Environment, Eindhoven University of Technology. The method does not focus solely on bending as such. Savings in the use of materials, reduced waste and efficiency during transportation and construction are also major considerations during the design and construction process. Credits: Arthur van Lier Build Environment, Eindhoven University of Technology Coaches/researchers: Gert-Jan Rozemeijer, André Jorissen, Arjan Habraken Companies: Verhoeven timmerfabriek, Adviesbureau Lüning www.mindthestep.nl/multicomplex.html



From excavated soil to loam construction materials

Photo’s: BC architects & studies/Thomas Noceto

Though a process of urban mining, BC materials converts excavated soil from docklands into circular loam construction materials. Each year, Brussels and Flanders excavate 22.5 million tons of soil. About 75 % of it is not polluted, and about 40 % of that is used in a non-circular manner for road building or dumped as waste. BC materials converts this soil into local construction products such as loam plaster, loam blocks and rammed-earth walls. Loamboard materials are never baked, but are composed of a correct proportion of granular size, type of grains and quantity of water, which is specific per loam construction technique.

BC Materials distinguishes soil types in five main categories: clay (less than 2 μ), silt (between 2 μ and 0.06 mm), sands (between 0.06 mm and 2 mm), gravel (between 2 mm and 20 mm) and boulders (between 20 mm and 200 mm). Each type of soil is characterized by a specific ratio of these different sizes. The clay materials are CO2-neutral, ensure according to BC Materials a healthy indoor climate and contain minimal gray energy. After use it can be returned to the soil or re-converted into building materials in an infinitely circular process. www.bcmaterials.org



Façade panels based on circular residual materials NPSP, together with students from Avans University of Applied Sciences, HZ University of Applied Sciences and TU Eindhoven, has developed façade panels based on circular residual materials. The result is a high-quality and durable façade panel that is strong, dimensionally stable and is sustainable. At the end of its useful life, the material can be ground and reused as the basic raw material in the same process. Nabasco 8010 is a bio composite, made off materials with low CO2 emissions, which are produced locally. Nabasco 8010 consists of fibres and a bio resin. The fibres come from mown roadside grass, recycled toilet paper (Recell), recycled textiles, waste cane and flax. The material also contains calcium carbonate, residual material from the softening process of drinking water and a bio based resin, based on residual materials from biodiesel production. The production was carried out by the students themselves. A dough was made on the basis of all fibers, calcium carbonate and resin, which was then pressed into a hot mold for a few minutes. NPSP (Dutch) > More at coebbe.nl (Dutch)>

Plastic stone tiles The majority of plastic waste ends up in the sea. This rises to the question how plastic waste behaves in nature. Under natural influences it forms plastiglomerate. A compound of plastic and natural geological components. Based on this, Enis Akiev investigated rock forming processes and developed methods to give lightweight packaging waste a natural-looking rocklike structure. Enis Akiev is a young material designer, born in Kazakhstan, raised in Germany and graduated at Köln International School of Design in 2018. Her main focus is sustainable materials for interior and exterior applications. By focusing on post-consumer plastic she wants to change the perception of waste and show its unique aesthetics. She thus increases the value of disposable packaging waste and makes it accessible as aesthetically pleasing and durable material. The plastic stone tiles-project should give impulses to rethink the general understanding of resources and to stimulate an exploration of materials. ‘With regard to the reduction of natural resources, we must consider waste more than ever as a resource and as a continuous step in a never-ending process, rather than the end of a product’s life,’ Akiev stated. www.ddw.nl>



Chaise longue with with variable stiffness by Henriette Bier and Arwin Hidding

Chaise longue with variable stiffness The chaise longue by researchers Henriette Bier and Arwin Hidding is a multi-functional chair created from 3D robotic printing. The chaise longue can change shape, making it possible to use the object as both chair and bed. The user can either sit or lie down by deforming the chaise longue with their weight. The shape change is achieved by combining variation in material distribution and the use of thermoplastic elastomers. Variable stiffness is employed in this project as an adaptation strategy to achieve multi-functionality. The actuation is implemented by the weight of the user. This shape change is achieved by combining variation in material distribution and use of thermoplastic elastomers (TPE). www.roboticbuilding.eu>




Plasma Rock Photo’s: Inge Sluijs

In the many rubbish dumps dotted along the British coast Inge Sluijs discovered - during her Masters studies at Central Saint Martins, London - the raw substance for a new material: Plasma Rock. Billions of tonnes of waste have been dumped worldwide over the past decades. In Europe alone, there are 500,000 landfills and certainly at coastal sites these ‘landfills’ are a barely controllable source of pollution for both soil and seawater. That’s why Sluijs chose a coastal location for the start of her project. She thought it should be possible to dig up the waste and use it for a better purpose. The search started after seeing a picture of a piece of Plasma Rock, then completely in the domain of scientific research. Plasma Rock is produced as a by-product when waste is gasified at very high temperatures. In addition to the energy released, this produces a mechanically strong and non-toxic type of material, the application possibilities of which have hardly been explored up to now. It is clear, however, that about a fifth of the total weight of mined waste can be converted into Plasma Rock. To be able to use Plasma Rock, it must first be broken into small pieces and then ground into powder. Sluijs used the raw material in the production of tiles and vases. Only the addition of binder


was required for the tiles; in the vases she also used recycled laboratory glass. Her role, Sluijs says, is to involve people in the story, helping them to realize that landfills are buried and left unexcavated purely to further all sorts of economic interests - including project development and housing construction. ingesluijs.wixsite.com>



Hey Jute The extremely long bark fibres of the jute plant, which grows mainly in the Bay of Bengal, is systematically torn to pieces in production processes. Only in some hand-knotted carpets does the fibre, which has a natural length of up to 5 m, occasionally prove its unique quality. When Alexander Marinus started his study on jute, the espadrille was his reference point: the shoe with a sole made from jute rope. In other applications too, he noticed, the jute fibre is mainly used ‘behind the scenes’. For example, as a layer in carpets and linoleum, or in potato sacks. His project was therefore not focused on the development of a new material, but on radically changing the perception and the appreciation of this natural fibre in textiles. Simply by finally using the actual properties of the raw jute fibre in its purest state - preferably the light-coloured, thin fibres.

sed it with his self-developed ‘needle instrument’, the more attractive the felt became, eventually acquiring the texture of fur. In addition to the economic significance that high-quality jute production can have for the regions where it is grown and processed, Hey Jute also seems an appropriate solution in the growing demand for materials that do not require the addition of any chemicals, which grow in a clean way (jute grows in a single rain season and does not require additional irrigation, fertilization or insecticides), and can be re-used. He did many of the experiments himself, supported lately by artist and felt speci-

alist Marian Verdonk. Together they are taking the first steps towards an industrial production process, although the right formula has yet to be found. Who should deliver the raw material? How should the fibre be removed from the plant? Where will the felt be made? And what specifications should the manufacturing process and the end result meet? Marinus hopes to answer these questions in the coming period. Simultaneously, the properties of the material will also need to be investigated further.


Marinus discovered that the long fibres made the material perfectly suitable for needle felting: the more he cros-

Denimtex: Jeans on the Wall

Every year in The Netherlands about 1.2 million discarded garments end up in the incinerator. That’s a shame. With Denimtex, a part of these textiles can be saved from the incinerator and unraveled into textile fibres by means of fibre machines that can be reused. Jeans on the Wall transforms fibres from jeans into ‘textile plaster’, a wall and ceiling finish with unique characteristics. Apart from its decorative appearance, the plaster has sound-proofing and insulating properties. The textile plaster can also be dismantled and reused. www.denimtex.nl> DDW>



Mussels in the 3D printer 3D-print technologies are increasingly utilized. There is more attention for this in the circular economy too. Unfortunately, most materials for printing are still far from sustainable. This project shows that this does not need to be the case. Mussel shells, local Zeeland refuse of which 20 million kilograms (44 million pounds) are produced each year, are completely recycled and reused. The material comprises a paste of ground shells, mixed with sugar water. Once the life cycle of a product has expired, the 3D print is dissolved in water for reuse. Mariet Sauerwein Industrial Design Engineering, Delft University of Technology Researchers: Zjenja Doubrovski, Joost Vette Mind the step>

The Wall project The exhibition ‘Re-invented crafts - a new perspective on Portuguese design’ showed the current state of Portuguese design. According to the DDW organisation two tendencies stand out clearly this year. 3D printing and computationally generated design are two of the focuses among this year’s designers. On the other side of the technology spectrum, experimentation and exploration of traditional local crafts is noticeable in the pieces of the selected designers. Local resources and a minimum amount of materials are used, complemented by the synergy between craftsmanship and technology. Like the Wall Project MAVC, developed by Maria Anna Vasco Costa. Her design process is driven by the experimentation of colour, textures an patterns, led by simple geometrical shapes. These shapes are inspired by Portuguese traditional monochromatic tiles. She explores new possibilities for the use of traditional ceramics by experimenting with patterns, temperatures, colours and glazing methods, set in an architectural scale. In The Wall Project the use of traditional tiles is transformed into contemporary surface designs. MAVC>



Hydroformed radiator During the entire Dutch Design Week the hydroformed radiator from EddyBoy was on display at the Klokgebouw. It is an idea of the Antwerp product developer Eduard Bartels, who designed various heating products under the name EddyBoy, including a heated outdoor bench. The hydroformed radiator would have emerged as a side-project in a search to deform sheet steel. The stainless steel radiator gets its shape by deforming the material with water under pressure. The shape is striking, no radiator is the same. The organic radiator can be heated electrically or by the central heating system.


BlueRoof: from sewage waste to roofing BlueRoof produces roofing material from so-called screenings. This screening material is a collective name for the solid components that are removed from the water in the first step of the water treatment plant. This material consists mostly of hygienic wipes, but objects such as

telephones, cans or even toys can be found there too. The development not only solves the problem of the screenings, which are usually burned, but also creates a more sustainable substitute for the lava granules that are now being applied on ‘green’

roofs. In 2019 a pilot will demonstrate the functioning of the product. www.blauwdak.nl



RE3 Glass: building with cast glass The Dutch Design Week facilitated a presentation of the RE3 Glass project (TU Delft). As part of their doctoral research at Delft University of Technology, and in collaboration with researchers from the University of Twente and the Southern School School of Art and Design, Telesilla Bristogianni and Faidra Oikonomopoulou are working on the development of cast glass as a building material. The reusable material is made of all kinds of waste glass and requires a minimum of material thanks to the clever geometry. The research took place within the framework of the 4TUBouw project RE3 Glass in which new generations of Recyclable, Reducible and Reusable cast glass components for structural and architectural applications were examined. The Re3 Glass project unites three strategies - reduce, reuse and recycle - that can greatly increase the sustainability of glass as a building material.

Crystal Houses

The Crystal Houses of MVRDV Architects (2016), realized in Amsterdam’s PC Hooftstraat, turned out to be an important study object. Would it be pos-

Building with cast glass requires more fluid, organic forms

sible to use ‘bricks’ made from cast glass as structural building material without the support of, for example, a steel frame? And would they be storm proof in a flat façade? An experiment showed the potential, but also clarified the problems for researchers. The construction process was complicated and, because

the bricks had to be glued, future re-use will be almost impossible, adding eventually to the creation of waste.

Cast glass

The rectangular shape of the original glass bricks did not match the nature of cast glass. After the glass form is removed from the kiln and cools down, tensions build in the material. That’s why cast glass requires more fluid, organic forms. This is precisely what Bristogianni and Oikonomopoulou realized in their next steps: a building block made of recycled glass, its rectangular shape pressed downwards at two points, and containing a cavity, partly created to conserve material. In this way, the components in the stack fit together almost seamlessly. In another variant, the shape is more reminiscent of the links of a bicycle chain. It’s the intention that they fit closely together without the use of synthetic glue, so that every building can eventually be dismantled and the components reused. RE3 Glass> More at Innovative Materials 5 2018 (pdf)>



Circular and bio based facade, 3D printed by robot The organization of the Dutch Design Week had organized the so-called ‘embassy of circularity’ in the Klokgebouw. There, more than thirty exhibitors sho­wed the possibilities of the combination design and circularity. This included a joint venture between DEMEEUW and Aectual that showed a 3D printed façade that is 100 percent circular (based on recycled material or bio-based material). The circular printed wall was presented earlier this year at the Provada fair and was realized in collaboration with tech company Aectual. The latter developed special software and 3D print robotics with which on-demand customization can be printed on an industrial scale. The technology can be used to make unique construction products for architectural purposes, like the interior for the Loft Ginza Flagship store in Tokyo, and the façade for the main building for the 2016 EU presidency in Amsterdam. www.demeeuw.com www.aectual.com Above: 3D printed panels at the DDW Below: Loft Flagshipstore Ginza, Tokyo Japan 2017. Design: DUS. Photo: Aectual



Photo: Juan Pablo Allegre

3D-knitted shells save on construction materials and time With just the press of a button, ETH researchers knit a textile that serves as the primary shaping element for curved concrete shells. Now they have used the new technology - KnitCrete - to create a five-tonne concrete structure for an exhibition in Mexico City. The formwork is made of a knitted textile: KnitCandela. Built at the Museo Universitario Arte Contemporáneo (MUAC) in Mexico City as part of the first exhibition of Zaha Hadid Architects in Latin America. KnitCandela is an homage to the famous Spanish-Mexican shell builder Félix Candela (1910 - 1997). It reimagines his spectacular concrete shells through the introduction of novel computational design methods and the KnitCrete formwork technology.


The heart of the four metre tall curved concrete shell at the exhibition in Mexico City is knitted. The structure’s formwork is a textile supported by a steel cable-net. The prototype KnitCandela marks the first application that this technology is being used on an architectural scale. The structure is collaboration with Zaha Hadid Architects Computation and Design Group (ZHCODE), and Architecture Extrapolated (R-Ex).


The KnitCrete technology was developed developed at ETH Zurich by the Block Research Group in collaboration with the Chair for Physical Chemistry of Building Materials, as part of the Swiss National Centre of Competence in Research (NCCR) in Digital Fabrication. According to ETHZ The KnitCrete technology is a novel, material-saving, labour-reducing


Photo: Lex Reiter

and cost-effective formwork system for the casting of doubly curved geometries in concrete. Following a digitally generated pattern, an industrial knitting machine produced the shuttering of the formwork for the shell structure: in 36 hours, it knitted a fully shaped, double-layered 3D textile consisting of four long strips, ranging from 15 m to 26 m in length. The lower layer forms the visible ceiling - a designed surface with a colourful pattern. The upper layer contains sleeves for the cables of the formwork system and pockets for simple balloons, which, after the entire structure is coated in concrete, become hollow spaces that help save on materials and on weight. Manufacturing a formwork for such a geometrically complex structure using conventional methods would cost substantially more in both time and material.

ment mixture. This initial layer was just a few millimetres thick, but sufficient to create a rigid mould; once it hardened, conventional fibre-reinforced concrete was applied. The technology behind KnitCandela was developed by Mariana Popescu and Lex Reiter as part of Switzerland’s Natio-

nal Centre of Competence in Research (NCCR) in Digital Fabrication research project. Mariana Popescu is a doctoral student with Philippe Block, Professor of Architecture and Structure at ETH Zurich, while doctoral student Lex Reiter studies with Robert Flatt, Professor of Physical Chemistry of Building Materials.


In the museum’s inner courtyard, the knitted formwork was tensioned between a temporary boundary frame and sprayed with a specially formulated ce-

Photo: Lex Reiter



Photo: Mariana Popescu

Popescu’s research shows that employing knitted textiles in architectural applications cuts down on material, labour and waste, and simplifies the construction process for complex shapes. According to ETHZ, KnitCandela also represents an evolution of the flexible forming system developed for the HiLo roof: a doubly curved, thin-shell concrete structure the Block Research Group developed for Empa’s research and innovation building NEST in 2017. (NEST is an innovative building concept of EMPA, the Swiss Federal Laboratories for Materials Science and Technology. NEST should help launch technology and products in the building and energy sector on the market sooner in conjunction with industrial partners). For KnitCandela, the ETH researchers produced the knitted shell in one go, whereas HiLo’s shell was made of a network of steel cables and a sewn textile. (See Innovative Materials edition 6 2017.) According to Popescu, knitting offers a key advantage that it’s not necessary to create 3D shapes by assembling various parts. With the right knitting pattern, they can produce a flexible formwork for any and all kinds of shell structures, pockets and channels just by pressing a button. For the construction industry, 3D printing is a major topic. Philippe Block says that, to a certain ex-


Photo: Mariana Popescu


Photo: Maria Verhulst

tent, his group’s pioneering method is a new form of 3D printing, only it doesn’t require a completely new kind of machine. A conventional knitting machine will do just fine. www.ethz.ch> See also ‘KnitCandela - A flexibly formed thin concrete shell at MUAC, Mexico City, 2018’ at Block Research Group>

Photo: Philippe Block

(Video: ETH Zürich/Block Research Group)



Mineral waste, a needed source material for the production of future prospective building materials

Alkali Activated Material technologies prove that the overall increasing quantity of mineral waste as an output of growing population, can stand for a unique position as source material for concrete materials. Earlier this year this conclusion was presented in the PhD thesis ‘Performance of admixture and secondary minerals in alkali activated concrete; sustaining a concrete future.’ Concrete is the world most widely used man-made material. The research by dr. Arno Keulen together with prof. H.J.H. Brouwers and assist. prof. Q.L. Yu in the Department of the Built Environment at Eindhoven University of Technology resulted in the development of an advanced and environmentally friendly new type of concrete, namely Alkali Activated Materials (AAM). Here, the binder/cementitious material is completely made from mineral waste or industrial by-products in combination with chemical activators. This new binding material (technology) is applied as supplement or alternative of traditional Portland cement to produce high quality and durable concrete.

materials, are increasingly investigated and already used in traditional Portland cement-­based concrete as partial replacement of cement. However, due to










Alkali Activated Materials

Mineral waste and by-products (i.e. slags and or ashes) are the output from industrial thermal processes such as steel production and power generation. Nowadays these mineral streams, often called supplementary cementitious

their worldwide availability in combination with their relatively stable potential pozzolanic or hydraulic properties, various types of slags and ashes are also


Figure 1 Composition and production method of AAM concrete

RESEARCH of great interest for the development of alkali activated binders to produce highly durable and eco-friendly AAM concrete products. Then, instead of using traditional Portland cement, waste minerals can be reused and applied as 100% precur­sor (binder) material in combination with alkaline activator (e.g. metal hydroxide and silicate), to finally form a stable inorganic (aluminate silicate dominated) polymer matrix, gluing sand and gravel to produce concrete materials (figure 1). The obtained results show that, by making special use of waste minerals (slag and ashes) as potential binder source, AAM concrete products even have improved concrete sustainability and durability properties. The AAM technology offers more technical modification options within the mixture designs, producing function building materials with local resources, in comparison to traditional Portland cement. These material ‘tuning’ options are mainly related and controlled by the mineral binder type, composition and content and the concentration and type of alkaline activator(s). In the end, these technological options are of great advance to the design, development and production of functional future prospective building materials. What are nowadays more recognized and needed at different areas in the world depend on their function and abundance or changing climate. Even though, at different regions in the world

Figuur 2a. AAM concrete road construction

local waste minerals can be applied as source material to produce AAM instead of importing traditional cements. For example, a higher steel slag content as a replacement of fly ash in the binder composition favors the matrix densification and the material strength development by forming mainly calcium dominated gel-structures (C-A-S-H). This consequently results in an increased durability performance such as reduced chloride migration rate and improved chemical resistivity within aggressive environments.

Application material properties

From a visual point of view, no significant differences can be observed between traditional and AAM concrete products, which helps the acceptance and application of AAM as new building material. This binder technology and a part of the generated results are implemented by a TECH company named SQAPE Technology. They introduce this technology in the market, stimulating the development and production of future prospective building materials, within the rela-

Figure 2b. AAM concrete bicycle road



Figure 3. Reduton, road widening elements

tively conservative building material industry. At the moment, two product lines named Reduton and RAMAC are active in the Dutch market. Reduton concrete pavement products (e.g. pavers, stones and tiles) are prefabricated and designed with an improved material sustainability and a significantly lower

CO2 emission (kg) per kilometer concrete element




78% CO2 reduction

4000 1,946


Portland cement


Figure 4. The difference between the CO2 emission per kilometer of AAM and traditional concrete


Shadow costs (euro) per kilometer concrete element

€ 800



environmental impact (further discussed in paragraph below). RAMAC, a ready-mix concrete, is mainly applied as sustainable and highly durable concrete for the construction of various types of roads, roundabouts and concrete floorings (figure 2a, b).

€ 731

€ 700 € 600 € 500

68% lower shadow costs

€ 400 € 300

€ 236

€ 200 € 100 €0

Portland cement


Figure 5. The difference between the shadow costs (euro) per kilometer of AAM and traditional concrete

RESEARCH Environmental impact and circularity One of the major added values of AAM concrete is its low environmental impact, e.g. low CO2 emission and low impact on the depletion of natural habitat, as mining of raw materials is excluded and waste minerals are applied. Model calculation, verified by independent institutes show a significant difference between AAM and traditional Portland cement concretes. For example, a calculation is made between prefabricated Reduton AAM and traditional Portland cement concrete elements. The elements are designed to broaden the current roadsides in case of safety precaution (figure 3). For every kilometer of road broadening, the total CO2 emission to produce AAM elements is up to ≈ 80% lower compared to Portland cement concrete elements (figure 4). Additionally, for AAM concrete, ≈ 65% lower environmental impact or so-called shadow costs is obtained (Fig. 5), which are the costs that need to be payed to overcome the environmental damage for the production of the concrete products. Furthermore, all concrete products have a certain life span and this research also showed the recycle potential of AAM concrete to aggregate at the end of the service life (figure 6). The obtained aggregate complies with the current EU standards for material technical and

Figure 6. Process scheme: From concrete to recycling

‘environmental’ perspective to be again safely applied in concrete production likewise that of traditional concrete aggregate. This makes AAM concrete materials also circular.

Start the circular economy

The world population growth directly leads to a significant increase of mineral waste. At the same time the world demands more future prospective building materials to develop and sustain the growth. Therefore, replacing natural source materials and finding synergy between both issues is a key factor, in terms of innovation on the reuse of waste minerals within building-sector.

Consequently, wastes become of high interest, as source material to produce more eco-friendly concrete. Author: Dr. Arno Keulen More info: www.linkedin.com/in/arno-keulen/ Earlier this year dr. Ir. Arno Keulen was promoted at Eindhoven University of Technology on the PhD thesis ‘Performance of admixture and secondary minerals in alkali activated concrete; sustaining a concrete future.’ The publication is online>

AAM concrete bicycle road, Zeewolde (Innovative Materials 6 2016)



4TU-Bouw Lighthouse project

‘Re-printing architectural heritage’ Additive Manufacturing (3D printing) technology has become a global phenomenon. In the domain of heritage, 3D printing is seen as a time and cost-efficient method for restoring vulnerable architectural structures. The technology can also provide an opportunity to reproduce missing or destroyed cultural heritage, in the cases of conflicts or environmental threats. The 4TU-project ‘Re-printing architectural heritage’ has taken the Hippolytuskerk in the Dutch village of Middelstum, as a case study to explore the limits of the existing technology, and to investigate the potential of 3D printing cultural heritage. Architectural historians, modelling experts, and industrial scientists from the universities of Delft and Eindhoven have engaged with diverse aspects of 3D printing, to reproduce a selected part of the 15th century church. This experimental project has tested available technologies to reproduce a mural on a section of one of the church’s vault with maximum possible fidelity to material, colours and local microstructures. The project shows challenges and opportunities of today’s technology for 3D printing in heritage.


RESEARCH Connecting new technological developments in 3D scanning and 3D printing with cutting-edge research in architectural design, the project aims at developing material reproductions of architectural heritage. Eventually the team selected a painting of an angel, riding a lamb, located in a vault near the choir. The painting depicts the last judgement, and is part of series of scenes made by Albrecht DĂźrer. Throughout the process of scanning and printing the section, the team encountered multiple challenges, varying from the incapability of the scanning technology to capture the existing cracks in the required resolution, to the high costs of speciality printing with particular materials, and the limited possibilities for combining both printing techniques for such a complex structure. In the absence of printing technology that can apply a color to a non-flat surface, it was decided to explore the opportunities of printing the painting on a thin film and applying it over a 3D printed structure with visible surface microstructures. In principle, the film print ought to take into account the deformation based on surface unevenness and curvature. While it is basically possible to generate a computer model deformation, the team decided to ignore this aspect for our pilot project. Having separated the structural printing and that of the film, the researchers opted to first experiment with materials for 3D structural (non-colored) 3D printing. The CAMlab of TU Delft produced a first gypsum test print without color, providing a good first impression of the surface structure. The scientists found that the thin lines produced by the gypsum print technology were insufficient to render the texture of a wall surface. Additional test prints were produced by QUBICX, to experiment with different materials.

Two methods

Two methods have been tested: one with MultiJetPrinting, another with Selective Laser Sintering. In the first case, one coloured sandstone model was produced on the 3D systems ProJet660Pro. The printer build the model layer by layer applying a thin layer of gypsum

powder on the print table. The coloured binder is printed on the gypsum layer following the shapes of the model for that particular layer. The binder is printed on de gypsum using the tech-nique of an inkjet printer. This system is also referred as MultiJetPrinting (MJP). The colour binder reacts with the gypsum powder hardening the material. After completing the print the nonbonded unused gypsum is being removed for reuse. The printed object will then be post processed with a chemical which results in vibrant colours and a strong model. The second model was printed using PA12 white (nylon) produced on an EOSint P770 SLS 3D printer.

The PA12 powder is spread on the print table layer by layer the same way like the first model. Only this time the material is bonded by using laser beams. The result is a very accurate and strong model. This technique is also referred as Selective Laser Sintering (SLS) Both of these objects had the qualities necessary to serve as sub structure. To reduce the cost of the printing material, the team decided to hollow out the piece and to apply spider-like/honey-comb back structure. For the front structure, several options were discussed. Because the inkjet option, appeared to be not suitable for this



project, they decided to print the final colors and textures on a thin flexible foil layer (50 microns) and fix it over the solid 3D structure, which in this case has all the microstructures, and grains visible. Reducing the glossiness of the material as much as possible, so the final product can be similar to the church mural, was addressed by applying an additional matt layer. A 3D test print consisting of four panels was first exhibited at the Gevel fair in Rotterdam in January 2018 and has since been shown to the public at two other events.


Combing 3D printing with a foil surface treatment allows conservators to experiment with reconstructions of the paintings from different time periods in comparison to the original. Such comparison is particularly effective when the print is viewed from a certain distance. Nevertheless, a number of challenges remain. As realized, the foil retains a certain glossiness that is not in line with the original ceiling painting. Furthermore, the four panels that combine into the


structure deformed slightly during the drying process and the separation lines remain visible despite the foil that covers them. This problem is partly due to the thinness of shell used in this case to save costs. Student proposals for a 3D printing of a Middelstum church vault based on novel design suggested a puzzle-like system that would imitate the original ornamentation of the church. Such an approach could be pursued in future approaches and would take into account the particular material and technical qualities of 3D Printing. The technology used in this project is not the only one tried out by the team. Research and pilot 3D print for a section of the Golden Room in the Mauritshuis will be discussed in a separate issue. Text: 4TU Bouw Thanks to Dick Vlasblom, QUBICX, prof. Carola Hein, professor of History of Architecture and Urban Planning Department of Architecture, TU Delft

Credits: - Delft University of Technology: prof.dr.ir. Carola Hein, dr. Michela Turrin, prof.dr.ir. Joris Dik, John Hanna, Miktha Alkadri, Serdar Asut, Prof.Dr.-Ing Ulrich Knaack, Peter Koorstra - Eindhoven University of Technology: prof.ir. Juliette Bekkering, ir. Barbara Kuit - Culrural Heritage Agency of the Netherlands: Albert Reinstra - National Archives: Angela Dellebeke - 3iD: Dave Vanhove - QUBICX: Dick Vlasblom - Foundation for Old Groningen Churches: Jur Bekooy - BLOMSMA PRINT&SIGN: Ron Teeuw


Hét expertisecentrum voor materiaalkarakterisering. Integer, onafhankelijk, objectief onderzoek en advies. ISO 17025 geaccrediteerd. Wij helpen u graag verder met onderzoek en analyse van uw innovatieve materialen. Bel ons op 026 3845600 of mail info@tcki.nl www.tcki.nl

TCKI adv A5 [ZS-185x124] Chemische analyse 14.indd 1

09-05-17 13:19

2017 volume 3


International edition Innovative Materials, the international version of the Dutch magazine Innovatieve Materialen, is now available in English. Innovative Materials is a digital, independent magazine about material innovation in the fields of engineering, construction (buildings, infrastructure and industrial) and industrial design.

3D-printing cellulose World’s first 3D-printed reinforced concrete bridge Materials 2017 Composites improve earthquake resistance in buildings

www. innovatievematerialen.nl info@innovatievematerialen.nl

Glass bridge Lina: world’s first bio-based car


Innovative Materials is published in a digital format, although there is a printed edition with a small circulation. Digital, because interactive information is attached in the form of articles, papers, videos and links to expand the information available.




Sustainable materials for smart cities As the speed of innovation is increasing and the earth’s population is growing, the past century has seen a 34-fold increase in materials consumption, resulting in large waste streams and associated CO2 emissions. It is widely recognized that this linear ‘take, make, dispose’ model cannot be maintained. A solution for this challenge is to keep structures and devices in use for as long as possible. This should be done with a minimum amount of materials preferably from waste streams, and should be economical and safe. The Materials innovation institute has, supported by a large consortium of partners from industry, universities and research institutes, taken the initiative to start a program to develop an new generation on building materials. The program is led by Prof. Dr. Daniel Bonn from the University of Amsterdam and focuses on steel and concrete, the materials that are used the most, so the program can have a maximum impact. The project has been submitted to the Netherlands Organization for Scientific Research and has the aim to enable ‘smart’ cities to realize a circular economy. As you can see in the enclosed model, collaboration between various parties will be essential to come to real solutions. All man-made products and structures are subject to environmental influences. There is a rapidly increasing need to understand and control degradation and reliability in all material classes due to the aging of existing structures. It is therefore essential to understand degradations mechanisms and to develop electronic sensors with multiple-decade lifetimes to better monitor the condition of structures and loads. This will help to reduce waste streams. Not all waste can be prevented, and techniques have to be developed to re-use materials once waste is created. An example of a project to recycle building materials is described in the next article by Siska Valcke from TNO. Dr. ir. Bert van Haastrecht, M2i


The Holistic Model (click to enlarge)

Fig 1. The holistic model of cross-over disciplines gives an overview of the inter-connections on 3 collaborating levels in the development of a next generation of CO2 reduced sustainable building materials. It explains the necessity of working cross-linked in a circular economy. Around the core of materials the three levels – the material level, the design & maintenance level, the policy & legislation level – include all the steps that need to be taken co-dependently and therefore cannot operate without each other


Optimal reuse of the fine fraction of recycled concrete Recently a new research project has started focusing on the optimal re-use of the fine–fraction of concrete in new concrete with TNO, M2i, TU Delft, RWS, Twee R Recycling, Cementbouw Recycling, AVG en BRBS Recycling The project is supported by the Dutch Topsector High Tech Systems & Materials (HTSM). In the Netherlands, yearly 33 Mton new concrete (roughly 15 million m3) is produced and 12 Mton concrete waste becomes available. The Dutch production of concrete is responsible for roughly 4 Mton CO2 emissions annually (nearly 2% of the Dutch national emission), and this is mainly caused by the cement content [1]. Recycling of the yearly 12 Mton concrete waste results in roughly 7 Mton coarse recycled concrete aggregate and 5 Mton fine fractions between 0 and 4 mm. A new application of the fine fraction in concrete is particularly becoming interesting now considering the fact that one of the current demands of recycled concrete, namely the application in road bases, is foreseen to reduce as the number of additional new roads planned in the dense Dutch road network is expected to decrease. So far, there are no optimised concrete applications such that the fine fraction can be sold at a price which would


RESEARCH cover the separation and storage costs. Furthermore, the recyclers are faced with variations in the fine fraction of which they do not yet know the optimal quality required for high end concrete applications. Current commercially available and upcoming separation techniques in the Netherlands are increasingly focussed on the advanced separation of concrete resulting in recycled coarse fractions with lower adhered cement contents and fine fractions in which cement paste is separated as much as possible from the original fine sand fractions. Different separation technologies lead to recycled concrete fractions that may have different physico-chemical characteristics, that is, different grain size distributions, shapes, textures with corresponding different chemical components. An even more important cause of variability in recycled concrete fractions, is the original composition and history of the parent concrete that is being processed. Many different types of concrete exist according to the applications and different exposure and usage during its life time may change the structure and bulk composition of the concrete. Variations in the recycled concrete are thus expected, particularly also in the finer fractions.


Recycled concrete

In the past 15 years, quite some research has been done focussing on the use of the fine fraction of recycled concrete for making new concrete. Concerning mix design, experimental works show the

effect of water absorption of the fine fraction and introduce possibilities for pre-wetting or additional water during mixing. Water content and superplasticizer influence the packing density to a great extent. As such, efficiently exploiting the particle packing effect, may

RESEARCH allow a.o. the application of fine recycled concrete particles as fillers that have continuous shape and grading characteristics for continuous quality products.


The Netherlands are frontrunner in terms of regulations on the use of secondary materials in concrete. However, they do not yet give clear guidelines for mix design for applying the fine fraction of recycled concrete for high quality new concrete applications at maintained or reduced cement content. The CUR Recommendation 106 [5] gives guidelines for applying fine recycled concrete as a replacement of the fine fraction of primary aggregate (sand) on the condition that the fine fraction is ‘non-reactive’ and contains no more than 10 % of particles that are smaller than 63 micron. The specific dry density should be larger than 2000 kg/m3 and the chloride content should be lower than 0.03 % m/m. If these conditions are met, then max 50% V/V sand replacement is allowed except for pre-stressed concrete with pre-tensioned steel. All in all, it is impossible to deduce without any further research the guidelines and tools to introduce the widespread application of the fine recycled concrete fractions in new concrete whilst keeping the cement contents at least the same or preferably lower. Namely, what is still missing is knowledge on the relation between the wetting suggestions and

the physico-chemical characteristics of the fine fraction, as well as knowledge on optimal packing and interaction with cement in order to keep cement contents low for high performance concrete and knowledge on the microstructure and expectance for long term behaviour of the new concrete. In other words: current regulations do not allow the application of the finest soluble recycled concrete fractions and do not provide guidelines for concrete mix design without increased cement contents for durable concrete applications The consortium has translated the industrial aim of efficient reuse of fine recycled into the more specific question: Which graded fraction(s) of cement, filler and sand in concrete mixes can be replaced by which graded fraction(s) of fine recycled concrete within 0-4 mm and what are the quantities needed to keep cement contents the same or lower for durable concrete? Therefore, the scientific aim of this project is to find the graded fractions resulting in both (1) optimal grain packing as well as (2) optimal interaction with cement and contribution to the binding capacity. In the project, various grain fractions of fine recycled concrete that are separated and processed in different ways will be examined. Physico-chemical characteristics are measured using state-ofthe-art techniques and methods, and these fixed models of grain packing and cement interaction are combined with the performance of optimized concrete mixes.

With this project the consortium aims to support and accelerate innovations in separation technologies for the recycling of concrete as well as applications with fine recycled concrete.

For more information please contact Iris Jönsthövel | Program Manager | Materials innovation institute (M2i), Mobile: +31 6 18 34 45 90| i.jonsthovel@m2i.nl of met TNO.

Literature 1) Bijleveld, M.M., Bergsma, G. C., Lieshout van, M. 2013. Milieu-impact van betongebruik in de Nederlandse Bouw. Status quo en toetsing van verbeteropties. CE Delft report, 66p. 2) Beton maken van Beton. Volkskrant 04-06-2018. https://www.volkskrant. nl/economie/wereldprimeur-voor-rutte-groep-beton-maken-van-beton-bc1 c6600/ 3) Rem, P., Di Maio, F., Gebremariam, A. 2018. Terugwinnen fijne fractie uit beton. Cement 4, 2018, p. 34-37 4) L. Evangelista & J. de Brito. 2014. Concrete with fine recycled aggregates: a review. European Journal of Environmental and Civil Engineering, 18:2, 129-172 5) CUR Aanbeveling 106:2014 (update foreseen). Beton met fijne fracties uit BSA granulaten als fijn toeslag materiaal.



Understanding Structure Formation in Hierarchical Hybrid Materials using Cryogenic Electron Tomography and Liquid Phase Electron Microscopy Introduction

The formation of biological hierarchical materials, as well as of many synthetic ones occurs from aqueous media. In these environments, material formation proceeds through dynamic processes of nucleation, self-assembly, and crystal growth. The complex 3D character of many of these systems, together with the size and fast migration of the building units in solution, limits the range of tools that can provide nanoscale insight into the formation mechanisms. However, recent developments in liquid-phase electron microscopy (LPEM) and advances in cryogenic electron tomography (cryo-ET, 3D cryoTEM), are increasing our capabilities to monitor materials synthesis in solution at different length scales.(De Yoreo et al. 2016; Patterson et al. 2017). These two methods deliver complementary information: LPEM produces a movie of materials formation with limited control over solution conditions, whereas cryo-ET provides higher-resolution with 3D analysis at fixed solution

conditions. The combination of these two techniques may be used to characterize many materials systems, including biological materials, composite films, vesicles, macromolecules and nanoparticles. A time resolved cryo-ET experiment together with a LPEM experiment in silicon nitride flow chips or graphene liquid cells should be the most detailed microscopy analysis on hierarchical hybrid materials formation at this moment.

Time resolved cryogenic electron tomography

In general, a cryo-TEM experiment involves the investigation of a thin vitrified film of solution/dispersion in which processes are arrested by plunging a thin layer of liquid on a cupper mesh into an appropriate coolant. Accordingly, the objects under investigation become embedded in a solid amorphous film of the solvent. To ensure electron transparency of the vitrified films, they are best prepared with thicknesses of less than 100 nm. The vitrification process allows time-resolved sampling of

Figure 1. Schematic of a liquid phase TEM experiment (left) in a SiN chip and of the collection of 2D projections from a frozen sample on a TEM grid at different tilt angles (right) to produce a 3D model of the existing objects through cryo- electron tomography


RESEARCH Liquid phase electron microscopy

LPEM provides a window into the dynamics of materials synthesis by allowing nucleation, growth and self-assembly to be controlled by reagent mixing, beam-induced deposition or thermally triggered reactions. Owing to this ability to probe processes occurring in the submicron-thick fluid films and provisions for both structural and compositional analysis, LPEM fills gaps left by cryo-ET experiments. (De Yoreo & N. A. J. M. 2016) Although the spatial resolution of LPEM is not comparable to cryo-TEM experiments, its temporal resolution is for example, higher than atomic force microscopy (AFM) which can only probe processes occurring on surfaces. LPEM is a fast growing technique, also from a chemical engineering point of view as it allows through the design of the cell/chip, a view into a nanoscale chemical reactor with microfluidic input and output. Figure 2. Schematic of a multi-scale self-assembly process from primary particles through material building block formation to macroscale crystal or confined arrangement coupling the structural dynamics to the evolution of size, and the relevant time resolution for investigation. Inspired by (Dey et al. 2010)

a reaction solution with a practical resolution of a few seconds. Arresting the sample dynamics enables the determination of 3D structure by cryo-ET, through the acquisition of a series of images from the same sample at different tilt angles and the reconstruction of the investigated volume. (Nudelman et al. 2011) Complex morphological transitions in macromolecular or multi-component systems are often difficult to follow in time resolved cryo-ET especially when the system is disperse and the structural evolution is not a single pathway for every particle (see Figure 2). In these cases, LPEM is an appropriate analysis tool to be used alongside cryo-ET.

Control and synthesis of complex polymer structures

The use of cryo-ET can provide essential details regarding the structure and to a certain extent, formation of synthetic macromolecular systems. Although cryo-TEM is now a widespread technique for the characterization of organic self-assembled structures, cryo-ET is still a relatively young approach to investigate non-biological materials, with an early example being the study of bicontinuous polymer nanoparticles (Figure 3a). (McKenzie et al. 2010; Parry et al. 2008; McKenzie et al. 2015) Here, cryo-ET was used to see the pathway of bicontinuous structure formation for tripeptide-containing amphiphilic double-comb diblock copolymers as well as for the block copolymer poly(ethylene oxide)-b-poly(octadecyl methacrylate) (PEO-b-PODMA). In addition, cryoTEM was used to monitor the different stages of the polymer assembly process that

Figure 3. (a) A 2D cryo-TEM projection image (i) and a 3D rendering (ii) of a poly[norbornene oligo(ethelene oxide)]–b-[poly norbornene GLF peptide] bicontinuous nanoparticle, and (b) sequential cryo-TEM images of cooling PEO-b-PODMA dispersions. (c) a cryo-TEM projection image (i) and a 3D rendering (ii) of a protruded polymer vesicle synthesized by polymerization of ethylene glycol dimethacrylate (EGDMA) in/on a surfactant vesicle membrane using living radical polymerization. (d) cryo-TEM shows the effect of different weight % of EGDMA in the monomer feed on the resulting 2d nanocapsules (a) is adapted from (Parry et al. 2008) with permission from WILEY�VCH. (b) Reprinted with permission from (McKenzie et al. 2010) Copyright 2018 American Chemical Society. (c, d) Reprinted from (Moradi et al. 2018) with permission from Elsevier


RESEARCH involved changes in the solvent composition and temperature. This demonstrates that, contrary to expectations, the bicontinuous nature of the particles is not formed upon changing solvent composition, but results (after complete removal of the organic solvent) from a reversible temperature transition in pure water. (McKenzie et al. 2016) Cryo-ET was also used to reveal the process of hybrid surfactant-polymer vesicle formation, where the vesicle structure evolves by varying the composition of monomers in a living radical polymerization at the surfactant vesicle surface (Figure 3b)(Moradi et al. 2018). Monitoring how protruded nanocapsule morphologies with different diffusion properties evolve from the living radical polymerization of a mixture of monomers with different hydrophobicity and reaction rates on a surfactant vesicle-surface further exemplifies how cryo-ET benefits materials synthesis. Understanding the details of these processes is the key to defining future research directions in the synthesis of these complex morphologies.

Monitoring polymer controlled mineral formation

In many biomineralization systems macromolecular assemblies control the nucleation and growth of different crystalline phases (Veis & Dorvee 2013). Charged biopolymers play a role in the stabilization of amorphous precursor phases from which many of these crystalline biominerals are formed. (Xu et al. 2018) However, their precise role in con-

trolling biomineralization is still not well understood. This lack of understanding is partially due to the difficulty of studying biomimetic mineralization systems with sufficient temporal and spatial resolution. As an interesting example, the nucleation and growth of CaCO3 in a matrix of polystyrene sulphonate (PSS) was visualized by LP-EM (figure 4), where the binding of calcium ions to form Ca–PSS globules is an essential step in the formation of metastable amorphous calcium carbonate (ACC) (Smeets et al. 2015). Here the method makes use of the fact that by analyzing particle development in time, the kinetics of the reaction could be extracted from which in turn the mechanism could be determined. The key finding was that ion binding can play a significant role in directing nucleation, and providing biology with a previously undiscovered tool to manipulate phase control, independent of any control over the free-energy barrier to nucleation.


Understanding material formation processes in and from solutions/dispersions is a complicated but essential task for materials chemistry. As discussed, cryoET can be used to observe the structural evolution of a wide range of materials under a variety of environmental conditions such as heating/cooling cycles or the interaction with reacting monomers. The combination of cryo-ET with LPEM can be particularly powerful for the investigating the kinetics of these transformati-

ons and provide a deeper understanding of the evolution of these nanostructures. Mohammad-Amin Moradi and Nico A.J.M. Sommerdijk, Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology. Parts of this research have been performed within the framework of the 4TU High-Tech Materials research program ‘New Horizons in designer materials’ (www.4tu.nl/htm). The project page can be found here: https://www.4tu.nl/htm/en/new-horizons/understanding-structure-formation/

References Dey, A., de With, G. & Sommerdijk, N.A.J.M., 2010. Chemical Society Reviews, 39(2), pp. 397–409. McKenzie, B.E. et al., 2015. Angewandte Chemie (International ed. in English), 54(8), pp.2457–61. McKenzie, B.E. et al., 2010. Journal of the American Chemical Society, 132(30), pp.10256–9. McKenzie, B.E. et al., 2016. Soft Matter, 12(18), pp.4113–4122. Moradi, M.-A. et al., 2018. European Polymer Journal, 108, pp.329–336. Nudelman, F., de With, G. & Sommerdijk, N.A.J.M., 2011. Soft Matter, 7(1), pp.17–24. Parry, A.L. et al., 2008. Angewandte Chemie, 120(46), pp.8991–8994. Patterson, J.P. et al., 2017. Accounts of Chemical Research, 50(7), pp.1495–1501. Smeets, P.J.M. et al., 2015. Nature Materials, 14, p.394. Veis, A. & Dorvee, J.R., 2013. Calcified tissue international, 93(4), pp.307–315. Xu, Y. et al., 2018. Nature Communications, 9(1), p.2582. De Yoreo, J.J. & Sommerdijk, N.A.J.M., 2016. Nature Reviews Materials, 1(8), p.16035.

Figure 4. (a) Image sequence after 45 min of (NH4)2CO3 diffusion, showing initial nucleation and growth of a CaCO3 particle inside or on a primary Ca–PSS globule within 4 s (i–viii) (ACC 1; scale bars, 20 nm). (b) Extrapolated growth rates versus average radius for two ACC particles (ACC 1 and 2 with PSS) compared against those of three vaterite particles (without PSS). (a,b) Reprinted from (Smeets et al. 2015) with permission from Nature publishing group


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