Increase in efficiency of formation structure process of the modified gypsum by carbonation

21st International Scientific Conference on Advanced in Civil Engineering "Construction - The Formation of Living Environment"

土木建筑工程

Petropavlovskaya, Victoria^1 ; Buryanov, Aleksandr^2 ; Novichenkova, Tatiana^1 ; Petropavlovskii, Kirill^1

Tver State Technical University, Af. Nikitin 22, Tver

170026, Russia^1

Moscow State University of Civil Engineering, Yaroslavskoe shosse 26, Moscow

129337, Russia^2

关键词: Comparative analysis;    Dry and wet conditions;    Environmental humidities;    Gypsum and carbonates;    Material compositions;    Mechanical characteristics;    Physical and mechanical properties;    Surface tension force;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/365/3/032061/pdf
DOI  :  10.1088/1757-899X/365/3/032061

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

The attention of leading scientists in the field of materials science is paid to the influence of moisture on the properties of disperse systems. It is noted that when the dispersed system is found for a long time in conditions of high humidity, moisture, after the formation of adsorption layers of maximum thickness, gradually accumulates in the gaps between the grains and is retained there by surface tension forces. It is established that the shrinkage of concrete products with a decrease in humidity at the time of its structure formation occurs due to an increase in the capillary contraction forces with a decrease in the thickness of the water interlayers. The introduction of the carbonate component into the composition of raw mixtures of composite products leads to changes in the character of the process of structure formation in gypsum systems, which requires the optimization of curing conditions. However, the issues of the effect of environmental humidity on the hydration of composite astringents based on semi-aquatic gypsum and carbonate additives, as well as on the formation and hardening of composites based on them, remain insufficiently studied. The paper presents the results of studying the dependence of the processes of structure formation in gypsum and composite gypsum-lime binders. The effect of curing modes and forced carbonization on the strength of composites obtained on the basis of a gypsum binder and a modifying additive is shown. The research used high-strength gypsum GVVS-16 of the Samara gypsum plant for samples obtained by injection molding technology. As an additive, the lime was used for the Uglovsky limestone plant in the Novgorod region. Samples were kept for 7, 14 and 28 days in air-dry and wet conditions. In addition, the samples were exposed to carbon dioxide for 6 days at a temperature of (20 2) ° C. A comparative analysis of the obtained materials on the strength and density was carried out according to the results of testing the samples by standard methods. Based on the results of the studies, the influence of the material composition of the modified astringent, the regimes of hardening and saturation with carbon dioxide on the process of structure formation and the physical and mechanical characteristics of gypsum materials was established. Thus, when modern modifying complexes are introduced into the gypsum binder, it is necessary to establish the optimum moisture regime. It should promote hardening of the material and reducing deformations in the structure of the hardening stone. The results of the studies show the combined effects of the addition of calcium hydroxide, forced carbonization, and optimal conditions for hardening. Optimal conditions of hardening contribute to the formation of a more dense structure of gypsum stone. Consequently, the physical and mechanical properties of the modified composite structure increase, the durability of the materials being designed.