Concrete is inherently brittle. This is a problem because important structures such as nuclear power plants need ductility to remain functional after earthquakes and impacts. Auxetic Cementitious Composites-3D (ACC-3D) aims at creating novel, ductile cementitious composites by using local reinforcement architectures with an unusual quality, negative Poisson’s ratio, known as auxetics.

Currently, steel rebars or fibers are used to make concrete ductile. Such reinforcement is only active once the concrete has cracked: it prevents existing cracks from growing. Cracking might leave structures unfunctional or vulnerable to repeated events and aftershocks. Can we make reinforcement actively work with concrete already before cracking by making it auxetic? This has never been attempted before.

Emerging auxetics with complex architectures fabricated by 3D printing offer excellent energy absorption capacity. However, they have low stiffness which makes them unsuitable for structural applications.

According to our preliminary study, using auxetics as reinforcement in cementitious composites will result in high energy absorption capacity. However, the mechanism of interaction between deformable auxetic reinforcement and the stiff cementitious matrix is unknown.

As a PhD candidate, you will work towards understanding these mechanisms through testing of the composite materials at multiple length scales using advanced experimental techniques such as in-situ X-Ray computed tomography and digital volume correlation. You will also develop optimization procedures for the composites based on machine learning.

The project "Auxetic Cementitious Composites through 3D printing (ACC-3D)" is funded by ERC as a Starting Grant 2021. ACC-3D is organized into 2 PhD and 2 postdoc projects who will work together with the supervisor in a complementary way. The candidate is therefore expected to enjoy working in a team.

You will work in the Microlab, our high-tech laboratory at the CiTG at TU Delft, dedicated to characterization and development of cementitious materials and will be embedded in the section Materials & Environment, which hosts more than 30 PhD candidates doing research on all aspects of the construction material cycle.

We are looking for an ambitious PhD candidate with:

• A MSc degree in a relevant field, i.e. Civil, Mechanical, or Aerospace Engineering.
• Knowledge and interest in experimental solid mechanics, cementitious materials, and additive manufacturing.
• Programming knowledge (e.g. Python).
• Experience/interest in machine learning and experimental research (in particular X-Ray Computed Tomography).
• Ability to work both in a project team, but also independently and take leadership and responsibility for research tasks.
• Excellent communication skills in English, both written and oral.

Doing a PhD at TU Delft requires English proficiency at a certain level to ensure that the candidate is able to communicate and interact well, participate in English-taught Doctoral Education courses, and write scientific articles and a final thesis. For more details please check the Graduate Schools Admission Requirements.

Fixed-term contract: 4 years.

Doctoral candidates will be offered a 4-year period of employment in principle, but in the form of 2 employment contracts. An initial 1,5 year contract with an official go/no go progress assessment within 15 months. Followed by an additional contract for the remaining 2,5 years assuming everything goes well and performance requirements are met.

Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2443 per month in the first year to € 3122 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance and sport memberships, and a monthly work costs contribution. Flexible work schedules can be arranged. For international applicants we offer the Coming to Delft Service and Partner Career Advice to assist you with your relocation.

Delft University of Technology

Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context. At TU Delft we embrace diversity and aim to be as inclusive as possible (see our Code of Conduct). Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale.

Challenge. Change. Impact! 

Faculty Civil Engineering & Geosciences

The Faculty of Civil Engineering & Geosciences (CEG) is committed to outstanding international research and education in the field of civil engineering, applied earth sciences, traffic and transport, water technology, and delta technology. Our research feeds into our educational programmes and covers societal challenges such as climate change, energy transition, resource depletion, urbanisation and the availability of clean water, conducted  in close cooperation with a wide range of research institutions. CEG is convinced that Open Science helps to achieve our goals and supports its scientists in integrating Open Science in their research practice. The Faculty of CEG comprises 28 research groups in the following seven departments: Materials Mechanics Management & Design, Engineering Structures, Geoscience and Engineering, Geoscience and Remote Sensing, Transport & Planning, Hydraulic Engineering and Water Management.

Click here to go to the website of the Faculty of Civil Engineering & Geosciences.

The department 3MD focusses on the design, construction and management of civil infrastructures and buildings. A multi-scale research approach is followed, starting at micro-scale (materials), to meso-scale (structures) and to macro-scale (infrastructures/systems).

Click here to read more about the department 3MD.