Impregnation and superhydrophobicity of coated porous low-fired clay building materials

The imperative needs of energy saving during the latest years indicate the necessity of producing hydrophobic building materials in order to increase their durability. In the frame of this experimental work, low-fired clay (roof tiles and facing bricks) have been subjected to impregnation to make them water-repellent. To achieve this, water- and solvent-based silanes/siloxanes have been selected enriched with Si nanoparticles. Generally the mechanism of these coatings is to reduce the water capillary absorption of the building materials which has penetrated, but does not clog pores or capillaries, therefore little or no impairment of the building material's ability to “breathe”.Different tests have been performed in the laboratory in order to test the efficiency of the tested solutions such as capillary elevation and water absorption. Additional the measurement and the evaluation of the thickness and the retention of the applied coating on the LFCM were performed using acoustic microscopy. This evaluation can be made in a repetitive way during the lifetime of the material targeting to the continuous monitoring of this effect.