Chemo-hydro-mechanical response of carbonatable cement binders

Towards neutral carbon building materials: Chemo-hydro-mechanical response of carbonatable binders through coupled X-ray and neutron high resolution imaging and modelling

Concrete is the single most widely used material in the world. Even when it employs recycled wastes from other industries (steel production for instance), its environmental impact remains important, notably in terms of the CO2 emissions involved throughout the process. Nonetheless, its unique mechanical strength, durability and comparatively low production price make it an unavoidable necessity in the foreseeable future. Recently, novel binders have been developed, that can reach the same mechanical properties as standard cement but whose hardening is caused by a carbonation process instead of a hydraulic reaction. These new binders allow therefore a significant reduction of the overall CO2 emitted during its production thanks to its CO2 consumption during hardening. This promising new technology is nonetheless in dire need of experimental investigations, which are so far limited to macroscopic measurements. These do not, in fact, provide understanding about the micro-scale processes driving the process at the engineering scale.

The aim of this project is therefore to bring local and quantitative experimental evidence about the spatial and temporal evolution of saturation density profiles. For this investigation, Neutron and X-ray imaging lend themselves as ideal probes. The understanding of the mechanisms involved in this process allows the development of chemo-hydric models (analytical or Finite Element ones) essential to the understanding and ensuing optimization of the process. This is a first step, at a pre-competitive level, but which is pivotal in the ongoing effort to reach the carbon neutrality of concrete production.



Chakib El Faqir is working on the chemo-hydro-mechanical response of carbonatable cement binders project. This project sees collaboration between the ESRF, ILL, Lafarge Holcim and UGA.