Abstract

Water is one of the main factors affecting the durability of porous materials and it is one of the most common causes of their degradation. Physical phenomena such as freezing or salt crystallization, as well as the development of fungi and moulds, are caused by the presence of moisture. In wet material thermal conductivity coefficient increases and the heat loss begins to rise. Hydrophobization is one of the protecting methods of porous materials against water. Two different type of water-repellent agents were used for the internal hydrophobization. The first of them is an aqueous emulsion of silane: triethoxy(octyl)silane (OTES) and the second one is also an aqueous emulsion but the matrix is poly(dimethylsiloxane) (PDMS). The paper focuses on the use of organosilicon water repellents. The main purpose of this paper is to determinate the possibility of use organosilicon agents as admixtures to internal hydrophobization. We compared results obtained for two different silicon-based admixtures. We investigated influence of both water-repellents on basic characteristics such as: absorbability, capillary water absorption and mechanical properties of cement mortar as well as heat of hydration of cement paste.