THE RELATIONSHIP OF CHANGES IN THE STRUCTURAL-PHASE COMPOSITION AND STRENGTH OF HYDROPHOBIZED CONCRETE UNDER THE INFLUENCE OF A CHLORIDE-CONTAINING MEDIUM
The relationship between the structure of cement stone and the mechanics of its destruction is established by studying the structural and phase changes occurring in cement stone under the infl uence of a highly aggressive chloride-containing medium. To ensure volumetric hydrophobization of concrete cement stone, it is proposed to introduce calcium stearate in the amount of 0.5 and 0.7 wt. % into the cement mixture at the manufacturing stage. Studies of changes in the physical and mechanical characteristics of cement stone samples were carried out aft er 6 months of exposure to a environment of a 2% Mg Cl 2 solution. Of the structural components of the studied brand of Portland cement CEM I 42.5N, low-base calcium hydrosilicates, portlandite and ettringite are more quickly decomposable during concrete corrosion in liquid chloride-containing media, which has a major eff ect on the change in the strength characteristics of concrete. As a result of exposure to liquid chloride-containing media, the compressive strength of concrete cement stone decreases by 35%. When the calcium stearate hydrophobizer is introduced into the cement mixture, a highly crystalline structure is formed during the hardening of concrete cement stone. In the structure of hydrophobized cement stone, the content of calcium hydrosilicates and ettringite is increased, resulting in an increase in strength. Aft er exposure to an aggressive chloride-containing medium, there is a slight decrease in the intensity of calcium-containing phases, the amount of portlandite in the cement stone structure does not decrease. As a result of chloride corrosion, the strength of hydrophobized concrete decreases by 8%.