Cement is the single most used material in the world, but despite many centuries of intensive usage and an ever-increasing worldwide demand, many physico-chemical fundamental questions regarding the cement setting process remain elusive. During this process different hydrates nucleate and grow, of which calcium silicate hydrates (C-S-H) is the most important binding phase. C-S-H is indeed the key compound controlling the final cement properties, such as strength and durability. Although a large deal of research effort has been devoted to the study of C-S-H, its poorly crystalline character has made it inherently difficult to fully characterize it. Moreover, the presence of aluminate phases both in ordinary Portland cement and in new low-CO2 emissions cement formulations result in Al-substituted C-A-S-H. Whereas much effort has been put in understanding the atomic structure of these phases, both the structure and diffusion of water through their pores remain poorly understood. Understanding water organization in the C-S-H phase is not only important for the setting behavior, but also because water plays a key role in the dissolution-recrystallization and carbonation processes which are the main cause of the loss of cement strength. Moreover, water diffusion in C-S-H nanopores is important to understand the exchange of other ions in pollutant removal or in the context of nuclear waste storage.
In this Ph.D. project, the atomic structure of C-(A)-S-H, and the structure and dynamics of water in the different pores of these materials will be studied using a combination of neutron scattering techniques, including neutron pair distribution function analyses and inelastic neutron scattering, with synchrotron X-ray scattering and laboratory-based methods such as water adsorption isotherms, infrared spectroscopy or thermogravimetric and calorimetric analyses. We are looking for a motivated candidate with a background in physics, materials science, or chemistry, with fluency in English, and a strong motivation to work in an international environment.
The PhD project will be located in Grenoble (France), at the ILL, and at the ISTerre laboratory (campus St. Martin d’Heres), in close collaboration with BRGM (Orleans, France). The successful candidate will be employed for a period of up to three years, with a gross salary of around 2350 €/month, together with other benefits depending on the student’s social status (for more details see: http://www.ill.eu/science-technology/phd-students/phd-recruitment/phd-work-at-the-ill/). A team of experts, including the geochemistry team at ISTerre, and interactions with experts from BRGM (French Geological Survey, Orleans), will supervise the work of the PhD student.
Applicants should have a degree in a relevant physics, chemistry or materials science discipline. Academic knowledge of condensed matter physics will be appreciated.
Supervisors: Alejandro Fernandez-Martinez, ISTerre (CNRS & Univ. of Grenoble Alpes), Alexander Van Driessche (CNRS & Univ. of Grenoble Alpes) and Gabriel J. Cuello, ILL (Grenoble).