Hydration of gypsum systems

Hydration process depends on a number of factors including water-to-gypsum ratio that depends on the specific surface area (granulometric composition). Increasing the specific surface area results in the varied dissolution rate, and thus,the solution concentration. The latter affects the initial framework structure and the formation of crystallization nuclei. Modifying the surface energy of crystals and solution concentrations with surfactants can change the rate of framework formation. Purpose. The research of the impact of modifiers in the form of surfactants on the main physical and mechanical properties of gypsum systems and the hardened structure. Conclusion. Considering heat release regions along with the solution concentration, framework formation and strength, it can be assumed that the framework formation occurs with an increased solution concentration and high heat generation rate. The second region (0.25-1.00 hour) probably refers to forming contacts between splices and filling large voids. The third region (1.00-2.00 hour) is of the utmost interest. Thus, using finely ground gypsum catalyzes the hydration process, though adding a large amount of finely grained additive into the ordinary building gypsum composition leads to a lower hydration rate. The formation of newgrowths after the framework is formed in a confined space results in higher internal stresses and a lower strength of the hardened structure, which has been proved by the results of the mechanical tests.