Impact of Silane and Siloxane Based Hydrophobic Powder on Cement-Based Mortar

Abstract

Impact of the addition of silane and siloxane based hydrophobic powders on cement based mortar was studied. Effect of powder addition on mechanical properties and water absorption of cement based mortar is described. Impact of accelerated ageing, including UV radiation, and rain-sun cycles on hydrophobic performance was assessed, demonstrating excellent durability of silane-based hydrophobic performance.

Influence of organosilicon admixtures on the hydration of Portland cement

“…where Ᾱ Γ (Γ hydr ) is a normalized chemical affinity related to the hydration degree, and β RH is an empirical coefficient [12] mentioned that silane powder gave better results than the other tested admixtures. As we can see the presence of organic groups (such as methyl, octyl, etc.)…”

“…But there is not enough research determining the impact of organosilicon, waterproofing admixtures on the hydration of Portland cement. Many researchers (see for example [1,[8][9][10][11][12]) made effort to understand and explain the Portland cement mechanism hydration in the presence of polymers. Polymer particles are mainly adsorbed on the surface of cement grains where the polymer cover is formed.…”

Internal hydrophobization of cementitious materials by using of organosilicon compounds

“…The addition of 2% PDMS based admixture did not affect the compressive strength, and the addition of 5% of admixture even caused an increase in strength. Spaeth et al [13], who used silane and siloxane based hydrophobic powder as admixtures, noted increase in compressive strength of mortar for silane powder and mix of silane and siloxane. While the reduction in mortar strength occurred for PDMS powder.…”

“…In all four cited papers [12,13,14,] authors noticed decrease in capillary water absorption. Spaeth et al [13] the best results achieved for silane/siloxane mix, but they also perceived that silane powder gave better results than siloxane admixture.…”

“…In 2010 M. Najduchowska and P. Pichniarczyk [12] investigated the influence of hydrophobic agents (among other polydimethylsiloxane (PDMS)) on the properties of cement and gypsum mortars. The impact of silane (n-octyltriethoxysilane) and siloxanes (PDMS) based hydrophobic powder on cement mortar, but with addition of zeolite, examined in 2013 V. Spaeth, J-P. Lecomte, M-P. Delplancke, J. Orlowsky and T. Büttner [13]. N. Milenković at el.…”