Hydrophobization
A new technology is impregnation of aggregates, which closes air gaps preventing water penetration with constant adherence of particles to the cement matrix. Hydrophobization of the aggregates and mortar decreases capillary water absorption, but still does not seal the pores or capillaries, which enables free vapor permeability . Water-soluble organic silica compounds, i.e., siloxanes, can be used as hydrophobizing agents in the amount of 1%–2% in relation to cement mass. The use of hydrophobization during lightweight block manufacture would eliminate the phenomenon of excessive moisture during exploitation of building objects. Additionally, it would offer considerable protection against transport of saline solutions into the brickwork, which would cause material destruction due to multiple processes of freezing and defrosting during wintertime and the phenomenon of dissolved salt crystallization. In addition, materials containing salt are characterized by higher moisture than materials that are free from salts. Excessive moisture significantly influences the heat flow process by an increase in heat conductivity of the materials and thus losses of energy.
The results of the present study can possibly be used to establish guidelines for practical applications of lightweight aggregates concrete with sewage sludge foamed by hydrophobic agents, which has slightly different characteristics compared to those of traditional lightweight concrete. The analysis of heat-moisture as well as physical and mechanical properties of concrete will confirm the usefulness of lightweight aggregates with sewage sludge addition for further production of energy-saving and ecological lightweight blocks. Introduction of new technologies of energy-saving materials in the building industry provides greater and significant potential, which would lead to a decrease in final energy consumption in the building and housing sector.
Suchorab, Z.; Barnat-Hunek, D.; Franus, M.; Łagód, G. Mechanical and Physical Properties of Hydrophobized Lightweight Aggregate Concrete with Sewage Sludge. Materials 2016, 9, 317.
Civil Scholar is a Blog by Aravind Samala on Construction, Environment, Technology, Trends and Innovation.