Title: Influence of Mixture Proportions and Permeability- Reducing Admixtures on Concrete Fluid Transport

Author(s): R. M. Ghantous, V. Bui, S. Schaef, B. Fronczek, C. B. Jablonski, S. R. Reese, and W. J. Weiss

Publication: Materials Journal

Volume: 120

Issue: 6

Appears on pages(s): 107-120

Keywords: concrete mixture design; degree of saturation (DOS); interfacial transition zone (ITZ); neutron radiography (NR); permeability; permeabilityreducing admixtures (PRAs); visual inspection

DOI: 10.14359/51739150

Date: 12/1/2023

Abstract:
This study uses neutron radiography (NR) and visual inspection to quantify water penetration in concrete samples exposed to water pressure on one face. It provides experimental data regarding the impact of mixture proportions on the hydraulic permeability of concrete. Specifically, it illustrates the influence of water-cement ratio (w/c), curing duration, entrained air content, and coarse aggregate (CA) size and volume on water transport. In addition, this paper quantifies the impact of permeability-reducing admixtures (PRAs) on water transport in concrete. It was observed that decreasing the w/c and/or increasing the curing duration reduced the fluid transport. Liquid and powder PRAs efficiently reduced fluid transport in concrete without impacting the compressive strength. The liquid PRA showed more consistent results, likely due to better dispersion than the powder PRA. Fluid ingress in concrete samples appears to increase with entrained air content due to a lower degree of saturation (DOS) at the start of the test. Increasing the CA volume fraction or decreasing the CA size will increase the fluid transport in concrete due to an increase in the connectivity of the interfacial transition zone. The influence of entrained air content, curing duration, CA volume fraction, and CA size was less noticeable on mixtures with PRAs due to the higher density and low permeability of these samples compared to control samples.