Modelling Pore Continuity and Durability of Cementitious Sealing Material Available to Purchase

In this paper the latest developments of the hydration simulation model Hymostruc are discussed while evaluating pore connectivity and the influence on permeability and durability of cementitious sealing material for carbon sequestration projects. The numerical model Hymostruc is used to quantify and visualize this phenomenon and to show the contribution of capillary pores to the continuity of the capillary pore system throughout an evolving microstructure. Once the capillary pores are blocked by ongoing hydration the transport of CO₂ gasses are restricted to migrate through the microstructure and avoid leakage of the sealing material. A blockage of the capillary pore system during evolution of the microstructure (pore discontinuity or depercolation) is, therefore, indispensable for a sound cementitious sealing material and must be one of the main objectives for the slurry design. The numerical model Hymostruc is used to evaluate existing literature-based slurry compositions on their ability achieve full depercolation of the capillary pore system in relation to the hardening conditions. Potential compositions of slurries are proposed and microstructural properties show the performance of optimized microstructures that comply with pore discontinuity. A durability evaluation regarding the CO₂ ingress is conducted as well. The pore continuity analysis shows the relevance to control of the capillary pore structure inside an evolving microstructure in relation to its permeability and it ease to leak gaseous phases through the sealing material.