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Doubling the Service Life of Concrete Structures. 1: Reducing Ion Mobility Using Nanoscale Viscosity Modifiers.


pdf icon Doubling the Service Life of Concrete Structures. 1: Reducing Ion Mobility Using Nanoscale Viscosity Modifiers. (187 K)
Bentz, D. P.; Snyder, K. A.; Cass, L. C.; Peltz, M. A.

Cement and Concrete Composites, Vol. 30, No. 8, 674-678, September 2008.

Keywords:

concretes; structures; mobility; viscosity; diffusion; nanotechnology; service life; electrical resistivity; additives

Abstract:

new approach for increasing the service life of concrete structures is presented. While conventional approaches have focused on producing a more impermeable matrix by reductions in water-to-cementitious materials ratio and the addition of fine particles such as silica fume, in the new approach, focus is shifted to the remaining pore solution through which diffusive transport will always be occurring. By adding appropriate nano-sized viscosity modifiers to the pore solution, conductive and diffusive transport can be reduced by basically the same factor as the viscosity increase relative to the viscosity of water (pore solution). Since in many degradation scenarios, service life is directly proportional to the diffusion coefficient of an ingressing ionic species such as chloride or sulfate ions, it is envisioned that a doubling of the service life of structural concrete can be achieved by increasing the pore solution viscosity by a factor of two. In part I of this series, viscosities of bulk solutions and electrical conductivities of solutions containing various concentrations of potassium chloride are examined to verify the viability of this revolutionary approach.