Construction and Building Materials

• The waterproofing effect of silane-based emulsion on foamed concrete was studied. • Water absorption decreased by 92.96% on coated foamed concrete with fly ash. • Freezing time of water was prolonged by silane emulsion coatings. • Deicing was significantly easier with all four coatings. • Superhydrophobicity from the emulsion coatings endowed self-cleaning properties. Foamed concrete has several attractive properties such as low unit weight, high thermal conductivity and good sound insulation as well as being compatible with most building materials. However, the process of forming foamed concrete can also lead to a porous structure within the concrete, leading to increased water absorption and structural defects. This study aimed to investigate the use of silane-based emulsion to reduce the water absorption of foamed concrete. Four types of silane emulsion were synthesized and coated onto the surface of foamed concrete. The hydrophobic performance improved at a temperature of −20 °C, when the waterproof layer was the thickest. The freezing time of water drops on the surface of the concrete was delayed by up to 157% compared to the uncoated control. The silane-based emulsion significantly improved the anti-icing property of the concrete, and they endowed the concrete with superhydrophobicity, creating a self-cleaning effect. These findings show that foamed concrete coated with silane-based emulsion can be used in a broader array of applications and environments.

Effect of silane emulsion on waterproofing and Anti-icing performance of foamed concrete