Doubling the Service Life of Concrete: A Nanotechnology Solution (VERDiCT)

1. Doubling the Service Life of Concrete: A Nanotechnology Solution (VERDiCT) Dale P. Bentz, Kenneth A. Snyder, Max A. Peltz Building and Fire Research Laboratory Jeffrey M. Davis Chemical Science and Technology Laboratory Viscosity and Conductivity 0.1 mol/liter KCl solutions INTRODUCTION The service life of concrete is often determined by the diffusion (rate) of a deleterious species such as chloride or sulfate ions from the environment into the concrete. This study examines the potential of a new technology called VERDiCT - Viscosity Enhancers Reducing Diffusion into Concrete Technology. Two studies are presented: 1) conductivity of ionic solutions with and without VERDiCT 2) penetration of chloride ions into mortars with and without VERDiCT Chloride Ingress (AgNO3) 7 d curing Large molecules are ineffective Nano-sized molecules are highly effective Quantifying Cl- Ingress into Mortars <----------------- 100 mm ----------------> 28 d curing CONCLUSIONS Nano-sized viscosity enhancers can significantly reduce conductivities and diffusivities Chloride ingress can be quantified using AgNO3 spray or X-ray microfluorescence MEASUREMENTS - Viscosity - Conductivity - Mass gain - Chloride ion penetration X-ray microfluorescence Ca-blue, Si-red, Cl-green AgNO3 spray