Modeling Electrokinetic Nanoparticle Penetration for Permeability Reduction of Hardened Cement Paste

Abstract

Electrokinetic nanoparticle treatments have been demonstrated to reduce the permeability of hardened cement paste by orders of magnitude. The origin of this approach stems from the tendency of particles to flocculate and precipitate when they make contact with pore fluid. The feasibility of a given treatment application is dependent upon the transport properties of the particle and of the cement paste. It is theorized that this process causes particles to fill the initial sections of pores to a large extent before further penetration is achieved. In this work a model was developed to predict the rate of penetration of a given nanoparticle treatment using the principle of superposition to combine the influence of electrophoresis, electroosmosis, and hydraulic flow. The model finds the penetration depth by dividing the net transport rate by the effective number of degrees of freedom in the pore system and multiplying by the treatment time. The model was found to compare well with experimental results, both for predicting if a penetration is possible and for predicting the extent of penetration.