Structure formation and properties of thermochemically modified silicate-sodium compositions

Yuri Gagarin State Technical University of Saratov, Department “Building Materials and Technologies”, Polytechnic St., 77, Saratov, Russia

^* Corresponding author: m-kochergina@list.ru

Abstract

Modern methods allow to improve the functional properties of silicate-sodium compositions. Increased water resistance primarily will allow their use in construction. The article presents the results of the study of modified silicate-sodium compositions by X-ray phase analysis, differential thermal analysis, thermo-gravimetric analysis. An organic zinc-containing compound, zinc acetate dihydrate, which is introduced into the binder in the form of a concentrated aqueous fluid, was used as a modifier. Using X-ray analysis, it was shown that in the hardening system “silicate-sodium binder an aqueous fluid of zinc acetate” in the temperature range 110-450°C various forms of hydroxides, silicates and zinc silicates are formed. In addition, at T = 450°C, only “traces” of ZnO were detected, and the crystalline phase of the hardly soluble zinc metasilicate ZnSiO₃ prevailed. The results of the study of modified samples by thermal analysis indicate the processes of thermal decomposition of the modifying additive in the binder system and indicate the possible formation of a new crystalline phase (ZnSiO₃) at a temperature of 440-450°C. It was revealed that temperature treatment of modified samples in the range of 440-450°C leads to a more significant increase in water resistance (by 25-28%) than during low-temperature curing (by 20-23%).