Evaluation of the Durability of Hydrophobic Treatments on Concrete Architectural Heritage
Abstract The protection of historical concrete structures is a challenge for the coming years. Hydrophobic treatment may reduce the deterioration process while providing protection against water penetration. Existing commercial products - mainly silane or siloxane in either water or solvent based formulations - were submitted to different ageing processes including UV radiation, dry-wet cycles, thermal shocks, freeze-thaw cycles, carbonation and their effectiveness has been evaluated on the basis of contact angle, vapour and chloride permeability and, capillarity water absorption. The results obtained clearly show that hydrophobic treatments display a good behaviour under the main ageing conditions.
Experimental Characterization of Injection Grouts Incorporating Hydrophobic Silica Fume
AbstractThis paper puts forward a new hydrophobic silica fume and assesses its contribution to the performance improvement of grouts for stone masonry consolidation. The experiments were conducted ...
Evaluation of thermodynamic properties of concrete substrates and cement slurries modified with admixtures
The study of the creation and the stability of the interface between concrete substrates and repair systems needs the knowledge of the thermodynamic properties of materials. The measurement of the surface free energies of liquids is realised by means of Wilhelmy plate method on reference liquid and repair products. In order to determine polar and dispersive components, it is necessary to measure the contact angle of these liquids and products on reference solid surfaces and on concrete, mortars and aggregates.Centrifuged solutions of repair product systems elements were prepared in order to measure surface free energies on pure liquids without solid particles in suspension. Evolution of properties versus time were also taken into account and analysed in comparison with well-known liquids and products.RésuméL'étude de la stabilité de l'interface entre un support en béton et un système de réparation nécessite la connaissance des propriétés thermodynamiques des matériaux. La mesure des énergies libres de surface des liquides est réalisée au moyen de la plaque de Wilhelmy sur des liquides de référence et des produits de réparation. Dans le but de déterminer les composantes polaires et dispersives de ces produits, il est nécessaire de mesurer les angles de contact que font ces liquides et produits sur des surfaces solides de référence.Des solutions centrifugées de produits intervenant dans les systèmes de réparation ont été préparées afin de mesurer les énergies libres de surface des liquides purs, en l'absence de particules solides en suspension. L'évolution de ces propriétés avec le temps est aussi prise en compte et analysée en comparaison avec des produits liquides et solides bien connus. Des conclusions sont tirées quant à l'utilité et la qualité de ces mesures pour la prédiction du comportement des matériaux durcis.