Speaker
Description
Water-bearing microfractures in concrete exhibit the ability to heal, leading to the closure of the fracture. Since concrete cracks provide a passage for chemical compounds that lead to the deterioration of the cementitious matrix and steel reinforcements, this self-healing capability is a crucial feature, enhancing the durability and longevity of concrete. One of the most important self-healing mechanisms is the precipitation of calcium carbonate, resulting from an intricate interplay between fluid flow, the concomitant transport of chemical species, and chemical reactions within the fluid and at the fluid-solid interface.
We aim to gain a better understanding of the underlying coupled hydraulic-chemical mechanisms and the influence of the fracture's aperture distribution on the self-healing through calcite precipitation. To this end, we have developed a numerical model that simulates the relevant processes within the void space along the fracture plane. FEniCS is used to solve flow and transport equations, while Reaktoro is used to quantify the chemical equilibrium and mineral kinetic reactions. The simulation results reveal that portlandite dissolution is the primary driver of calcite precipitation, as it increases both the pH value and calcium concentration. Furthermore, the model demonstrated that a right-skewed aperture distribution (e.g., exponential distribution) is vital for the degree of initial flow-rate reduction through calcite precipitation, as observed in the experiments.
| Country | Germany |
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