Chemo-Mechanical AGIng of Cementitious materials (MAGIC)

'What'

MAGIC aims to: 
•    quantify the chemo-mechanical multi-scale evolution of cementitious materials under the chemical degradation expected in repository environments. To identify the main reactive pathways at the repository scale during the re-saturation phase and at the saturated conditions.  
•    obtain a reference chemo-mechanical model of Portland and low-pH concrete exposed to relevant disposal environments, considering representative boundary conditions. 
•    estimate the extent of the impact of microbial activity on concrete properties (low-pH and Portland cement) in partially and fully saturated media.
 

'Why'

Nowadays, most of the experimental data are limited to the short-term material evolution and the long-term mechanical integrity of the cementitious material remains largely unknown. Following knowledge gaps have been identified:

•    What is the impact of various chemical degradation phenomena on the mechanical behavior of massive cementitious materials?
•    What is the impact of microbially induced processes in the chemo-mechanical behavior of cementitious materials? Do these processes change the chemical evolution which is expected to occur without microbiological activity?
•    How to model the long-term mechanical behavior of cementitious materials during hydraulic transients or fully saturated media with respect to the chemical evolution with and without microbial activity? 
•    How to achieve a comprehensive model based description of the multi-scale modelling process?  
 

Major highlights (June - Nov 2022)

- The initial SOTA of MAGIC was delivered in November. 29 persons worked on the document to give a detailed overview of the current knowledge about cementitious materials in DGD. 
-    All experimental and modelling works are in progress. A part of studies are well advanced with interesting experimental results especially on low-pH cementitious materials exposed to Mg disturbances with quantitative measurement of chemical and mechanical changes. 
-    Significant changes of mechanical properties (deacreasing of Young modulus) were also measured on low-alkali cement (LAC) concrete close to the interface with Opalinus clay.

Forward look

- Main part of results will be acquired during the second part of the year 4 and the first semester of year 5. 
- The existing data (previously mentioned) will be useful to test the modelling under development.