Analysis of the physical properties of hydrophobised lightweight-aggregate mortars
Danuta Barnat-Hunek, Piotr Smarzewski
Quarterly No. 2, 2016 pages 96-102
DOI:
keywords: hydrophobisation, mortars, physical parameters, thermal conductivity coefficient
abstract The article is devoted to assessing the effectiveness of hydrophobic and air entraining admixtures based on organ silicon compounds. Mortars with lightweight clay aggregate were the subjects of this investigation. Hydrophobisation of the mass was performed using a hydrophobic admixture and surface hydrophobisation was produced using a methyl silicone resin solution with a high VOC content, a water-based emulsion of methyl silicone resin in potassium hydroxide (KOH) and low molecular alkyl-alkoxy-silane in organic solvents. In this paper, measurements of the basic mechanical and physical parameters were carried out. Compressive strength, flexural strength, density, open porosity, total porosity, absorptivity, capability to diffuse water vapour, frost resistance, sodium sulphate corrosion resistance and the thermal conductivity coefficient were determined. The mortars show high absorptivity of about 26%. Hydrophobisation is ineffective after the period of 14 days - the longer the contact of the preparation with water, the weaker the effectiveness of impregnation becomes. All the samples used in the research demonstrated good resistance to salt crystallization after 15 cycles. Impregnation by the use of mineral waterproofing grout (L2) does not protect to a sufficient degree mortar with lightweight aggregate against damage caused by frost. However, surface hy-drophobisation had a considerable impact on the frost-resistant properties of the mortars.