Chip lets scientists study biocement formation in real-time

Scientists from EPFL and the University of Lausanne have used a chip that was originally designed for environmental science to study the properties of biocement formation. This material has the potential to replace traditional cement binders in certain civil engineering applications.

The chip has the size of a credit card and its surface is engraved with a flow channel measuring one meter from end to end and as thick as a human hair. Researchers can inject a solution into one end of the channel and, with the help of time-lapse microscopy, observe the solution’s behavior over several hours. Medical scientists have used similar chips for healthcare applications, such as to examine how arteries get clogged or how a drug spreads into the bloodstream, while environmental engineers have applied them to the study of biofilms and contaminants in drinking water.

Until now, the microfluidic chip was used in the medical and environmental research. © Alain Herzog / 2022 EPFL

Now, a team of civil engineers at EPFL’s Laboratory of Soil Mechanics (LMS), together with scientists from the Faculty of Geosciences and Environment at the University of Lausanne (UNIL), have repurposed the chip to understand complex transport-reaction phenomena involved in the formation of new kinds of biocement. Ariadni Elmaloglou, a PhD student, together with Dimitrios Terzis, one of her thesis supervisors from EPFL’s Laboratory of Soil Mechanics (LMS), injected biocement solutions into microfluidic chips resembling different types of sand to see how the minerals form and the flow responds. Besides the sand types, the other main biocement ingredients – calcium and urea – remained the same. “Thanks to the chip, we were able to observe variations in biocement mass distribution in the different mixtures,” says Elmaloglou. “For instance, we could see where minerals were formed and which mixtures can lead to superior mechanical properties across the long flow path. Due to its miniaturized volumes, the chip enables us to perform multiple experiments with different mixtures in order to design efficient biocementation protocols.”

Due to its miniaturized volumes, the chip enables us to perform multiple experiments with different mixtures in order to design efficient biocementation protocols.

Ariadni Elmaloglou, a PhD student, EPFL’s Laboratory of Soil Mechanics (LMS)

Meter-long testing

The engineers’ findings have just been published in Scientific Reports, a Nature portfolio journal. Theirs is the first study to examine biocement formation over the length of a meter in real-time, which is important for many potential applications such as crack repair, carbon storage and soil remediation (see box). All the data have been made available in open-source format in order to encourage further research on this topic.

Meanwhile, the LMS engineers have already started the next step of their study. “The chip makes it easy for us to test biocements made with aggregates of recycled materials – like glass, plastic or crushed concrete – rather than sand,” says Terzis. These biocements could help mitigate the construction industry’s carbon footprint, or even revolutionize the industry altogether. “The industry still relies heavily on concrete, even though the ingredients used to make it – especially sand – are getting harder to source. Our study shows that a cross-disciplinary approach can go a long way towards changing that. But we need to be open to methods from other research fields.”

Inventing new kinds of biocement at EPFL
For his PhD thesis at LMS, Dimitrios Terzis developed a new kind of biocement made with bacteria and urea. The process involves the use of calcium carbonate (CaCO3) crystals to bind soil particles together, instead of cement clinkers. The result is a material that’s bio-based, easy to use, resistant and fairly low cost compared with existing binders, including cement, lime and industrial resins. Resins in particular can become relatively unstable over the long term, can contaminate the soil with microplastics or toxic compounds, and can increase groundwater alkalinity to levels above acceptable limits. The EPFL-developed biocement can be produced on site cheaply and at ambient temperature, with only a small amount of electricity required. Operators can adjust biocementation levels to their specific needs. If only a small amount of CaCO3 is added, operators obtain a sandstone-like result that’s resistant enough to withstand the earthquake-induced shear stresses that can lead to soil liquefaction. Other applications can help resolve slope stabilization problems or restore existing foundations. If more CaCO3 bio-minerals are added, the result is a mixture that can be used as a construction material or for waterproofing soil. To take their technology to market, Terzis and Prof. Lyesse Laloui founded MeduSoil, an EPFL startup, in 2018. The firm has already carried out field demonstrations in Switzerland and abroad.


European Research Council Advanced Grant: Bio-mediated Geo-material Strengthening for engineering applications (BIOGEOS)


Ariadni Elmaloglou, Dimitrios Terzis, Pietro De Anna and Lyesse Laloui, “Microfluidic study in a meter-long reactive path reveals how the medium’s structural heterogeneity shapes MICP-induced biocementation,” Scientific Reports, 15 November 2022

Author: Sandrine Perroud

Source: Architecture, Civil and Environmental Engineering | ENAC

Professor Lyesse Laloui delivers the prestigious Vienna Terzaghi Lecture

© 2022 EPFL

The Vienna Terzaghi Lecture 2022 has been awarded to, and presented by, Professor Lyesse Laloui of EPFL at this year’s Austrian Geotechnical Conference on the 19th of April. Since 1997, the combined lecture and award have been given biennially to internationally renowned geotechnical engineers by the Association of Austrian Drilling, Well Construction and Foundation Engineering Companies (VÖBU), the Austrian Association of Engineers and Architects (ÖIAV), the Austrian National Committee (ASMGE) of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE) and the Institute of Geotechnics, Foundation Engineering, Soil and Rock Mechanics at the University of Vienna.

This year’s winner, Professor Laloui, is Chair Professor of Soil Mechanics and the European Vice President-elect of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE). His lecture titled, “Tailor-made soil properties by bio-geochemical means” presented his latest research on the multiphysical analysis of bio-cementation processes in nature and their practical engineering applications.

The lecture is named in honor of Karl von Terzaghi, who is considered the founding father of soil mechanics, a field of engineering exploring the mechanics of soils and its application in geotechnical engineering. His radical work on the properties of soils led him to develop unifying concepts on earth pressure and slope stability.

© 2022 EPFL

Throughout his distinguished career, Professor Laloui has looked to apply and build upon the fundamentals that Karl Terzaghi developed. Terzaghi observed, “Rainfall-induced pore pressure hike is not the cause of landslides, but a contributing factor. There were many higher hikes in the geological past! The cause is long-term gradual, cumulative chemical weathering which weakens inter-granular bonds which leads to decrease of cohesion”.

These pioneering ideas became the foundational theory behind Laloui’s latest research project BIOGEOS, an ERC-funded exploration of the interaction between water and soils which, rather than decreasing the cohesion as described by Terzaghi, strengthens it through natural bio-cementation.

Author: Brendan Smith

Source: Soil Mechanics Laboratory

Using electric current to stabilize low-permeability soils

EPFL scientists have developed a new approach to stabilizing clay soils. The method involves using a battery-like system to apply electric current to carbonate and calcium ions in order to promote soil consolidation. Their findings were published yesterday in Scientific Reports.

According to figures released by the UN yesterday, natural disasters have killed more than 1.2 million people since 2000 and cost nearly $ 3 trillion.These pressing threats bring into sharp focus the need for new answers to the problem of soil stabilization. Scientists at EPFL’s Laboratory of Soil Mechanics (LMS) have developed a number of sustainable solutions, including one that uses enzyme metabolism. Although these methods work for a wide range of soil types, they are considerably less effective when it comes to clay soils. In a paper published yesterday in Scientific Reports, the team demonstrates how chemical reactions can be enhanced by using a battery-like system to apply electric current.

A new type of biocement – produced in situ and at ambient temperature – has recently been put forth as a promising method for stabilizing various soil types. The method harnesses bacterial metabolism to produce calcite crystals that durably bond soil particles together. This biogeochemical process is energy-efficient and cost-effective, and could be rolled out quickly in the coming years. But since the ground needs to be impregnated for the method to work, it is less suited to low-permeability clay soils. Now, the LMS team has developed and successfully tested a viable alternative, which involves applying electric current using sunken electrodes. “Our findings show that this geoelectrochemical system does indeed influence key stages of the calcification process, especially the formation and growth of the crystals that bind the soil together and enhance its behavior,” says Dimitrios Terzis, a scientist at LMS and one of the co-authors of the paper.

The biocement is formed by introducing chemical species into the soil. These include dissolved carbonate and calcium ions, which carry opposite charges. Sunken anodes and cathodes are used to create an electric field, much in the same way as a giant battery. The current forces the ions to move across the low-permeability medium, where they intersect, mix together and eventually interact with soil particles. The result is the growth of carbonate minerals, which act as links or “bridges” that enhance the mechanical performance and resistance of soils.

Technology transfer grant

The paper, which sets out the team’s findings from observing and measuring the quality of these mineral bridges, paves the way for future developments in the field. Further tests, at different scales, are needed before the technology can be applied in the real world. The research was carried out under a 2018–2023 European Research Council (ERC) Advanced grant awarded to Prof. Lyesse Laloui, who heads the LMS and is a co-author of the paper. The project has three verticals, targeting the understanding of the fundamental mechanisms that occur at the soil-particle scale (micro-scale), the advanced characterization of mechanical behaviors at laboratory scale, and the large-scale development and demonstration of innovative systems in natural environments. In July 2020, the same research team obtained an additional ERC Proof of Concept grant to accelerate technology transfer to industrial applications.

In the past, soils were treated solely as a mix of solid earth, air and water. According to the co-authros, this research highlights how cross-disciplinary approaches i.e., drawing on concepts from biology and electro-chemistry and incorporating advances and mechanisms from other scientific fields can open exciting new paths and yield significant benefits.






Source: EPFL homepage

Biogeotechnics Webinar – 5 Little Known Keys For Successful Biogeotechnical Practice

Our team is so proud for the warm welcome our webinar and its interactive nature received from our community! Thank you for attending and for your follow-up questions and messages! We look forward to meeting you at our next webinars!

Update: The highlights of our webinar our now available online:

Biogeotechnics Webinar – 5 Little Known Keys For Successful Biogeotechnical Practice


The vast majority of infrastructure assets are constructed with or on unsuitable soils, which must be improved prior to, or after, construction. Conventional ground improvement technologies have historically relied on cement- and petroleum-based materials, perceived as straightforward commodities. This view can no longer be sustained due to the large volume and machine-intensive operations required, along with the resultant high carbon footprint and environmental damage. This webinar will present an alternative approach to material design and delivery using natural organic systems present within the soil to precipitate carbonate minerals that act as soil-binding agents. Technical discoveries and developments of bio-cemented soils will be presented, with a particular focus on how this technology can be integrated into mainstream geotechnical practice. Through the following points, under the scope of the ERC-funded BIOGEOS project, this talk will highlight to researchers and practitioners alike, the opportunities of a technology that will shape the future of low carbon soil remediation and stabilization practices:

• Applications & performance of bio-cemented soils
• Breaking the nitrogen barrier in biotic calcification
• Economics & environmental impact
• Equipment & monitoring
• Industrial practice: guidelines for successful integration


Prof. Lyesse Laloui
Professor Lyesse Laloui is the director of the Soil Mechanics Laboratory of EPFL. He is the recipient of the Advanced ERC Grant for his project BIOGEOS (BIO-mediated GEO-material Strengthening). He also received an ERC Proof of Concept Grant in 2020, to bring his research from lab to market. Founder and Editor-in-Chief of the Elsevier Geomechanics for Energy and the Environment journal, he is a leading scientist in the field of geomechanics and geo-energy. He has written and edited 13 books and published over 320 peer reviewed papers; his work is cited more than 6500 times with an h-index of 42 (Scopus). Two of his papers are among the top 1% in the academic field of Engineering.

Dr. Dimitrios Terzis
Dimitrios is a Scientist and Lecturer at the Swiss Federal institute of Technology, Lausanne (EPFL). In 2017 he obtained his PhD in Mechanics from EPFL. He has co-authored over ten peer-reviewed publications focusing on research and development around soil bio-cementation. He is the co-inventor of three patents which introduce niche elements towards efficient upscaling, environmental and economic applications of bio-geo-technical systems. He is the recipient of innovation grants and awards which sum up to over a million CHF. In 2018 he co-founded the EPFL spin-off MeduSoil which designs and delivers real-world systems based on bio-cementation to serve mainstream geotechnical projects. Since 2019 he is the principal lecturer and organizer of the course “Innovation for construction and the environment” which is taught in the Civil Engineering section of EPFL.

Maren Katterbach
Maren is head of department and a consulting engineer with Lombardi Engineering Ltd. in Switzerland.  Maren has been involved in a variety of projects, including underground construction, foundation stability, dam construction, and safety assessments. Within the framework of various dam projects in Europe, Africa, Latin America and Asia, she has provided expertise in the roles of consultant or designer for major foundation grouting works. Maren provides technical support to the EPFL spin-off MeduSoil, where through her role as the company’s CTO, she is designing and implementing real-scale solutions of the novel technique, which combines technical innovation, with economic efficiency and environmental responsibility in grouting applications.

Dr. Alexandra Clarà Saracho
Alexandra is a Postdoctoral Researcher at the Laboratory of Soil Mechanics at EPFL. She holds a MRes in Future Infrastructure and Built Environment (2016) and a Ph.D. in Geotechnical Engineering (2020), both from the University of Cambridge (UK). Her Ph.D. research investigated the application of biocement for the erosion control of sands and was the product of an industry-academia collaboration between University of California, Berkeley (USA), Hiroshima University (Japan), the University of Cambridge, and Japan Oil, Gas and Metals National Corporation.  Passionate about interdisciplinary approaches, her current research focuses on the design of carbonate-based biomaterials and delivery strategies that are coupled with end geotechnical applications, resulting in increased functionality.