Effect of chemical admixtures on water penetration of concrete
Author(s): M. Hassani, K. Vessalas, D. Baweja, Z. Schmidt
Paper category: Workshop
Book title: RILEM International workshop on performance-based specification and control of concrete durability
Editor(s): D. Bjegović, H. Beushausen, M. Serdar
Pages: 209 - 216
Total Pages: 8
Durability of concrete is in part determined by its resistance to the penetration of deleterious substances entering as a liquid or gas that is considered to be a function of its permeation capacity. Permeation capacity is controlled by the connectivity of pores that exist in the cementitious matrix and paste-aggregate boundaries. The presence of chemical admixtures in a mixture can greatly reduce the permeation capacity of hardened concrete by several orders of magnitude. Permeability-reducing admixtures are effective in blocking capillary pores by making them hydrophobic as well as depositing pore-blocking products into the pores.
This paper presents an experimental study into the effectiveness of using permeabilityreducing admixtures including hydrophobic pore blockers and crystalline self-sealers. Concretes with increasing w/c ratios of 0.4, 0.5 and 0.6 have been investigated. The effect of admixtures on water penetration has been assessed through monitoring the changes in mass transport mechanisms. In addition to the available standard test methods, the coefficient of permeability of water has been directly determined using a specially developed test method described in this paper. Results indicate that permeability-reducing admixtures can reduce the water penetration of concrete significantly if used correctly and if the design intent is defined.
Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00