Modelling the evolution of microstructure and transport properties of cement pastes under conditions of accelerated leaching

摘要

Calcium leaching might be a significant degradation process in concrete and reinforced structures with an anticipated long-term service life such as nuclear waste disposal systems or large hydro structures (dams, bridges, water tanks). The leaching process is extremely slow under environmental conditions, which fosters the use of accelerated experimental approaches such as leaching in an ammonium nitrate (NH4NO3) solution. In this paper, we develop a one-dimensional diffusion-based transport model with the purpose to predict the changes in microstructure and transport properties of saturated cement pastes in contact with a NH4NO3 solution. The model helps to better understand the transient state of leaching which is difficult to observe by experimental work.