Reducing uncertainty in the characterization and modeling of reactive transport processes in blended cement mortar

Abstract

Cements blended with industrial byproducts are ubiquitous construction materials widely used in waste management. The use of blended cements as barriers for nuclear waste management necessitates prediction of durability and long-term performance. A key component of durability prediction is mechanistically based reactive transport modeling. This work identifies critical parametric and model uncertainties within three key components of reactive transport modeling for blended cementitious materials: mass transport, mass conservation, and thermodynamic characterization. Studies of electroneutral ionic diffusion and the electrostatic interaction of dissolved ionic species and charged cement pore surfaces suggest that the influence of electrical interaction on transport may be more significant than previously surmised. A novel technique for measuring the elemental composition of reacted cementitious material in mortars compares favorably with established laboratory leaching techniques. Thermodynamic parameters developed for unblended cements are demonstrated to be generally applicable to the description of blended cements in both equilibrium and reactive transport modeling.