Eco-friendly construction materials: Lime clay gipsum plaster mixtures

¹ Karakalpak State University named after Berdakh, Uzbekistan
² Moscow State University of Civil Engineering, 129337 Moscow, Russia

^* Corresponding author: Aushakov@mgsu.ru

Abstract

Clay-gypsum raw materials and binders based on them are among the local building materials of the Republic of Karakalpakstan, and their use makes it possible to regulate the import of gypsum binders and its derivatives, thereby optimizing supply chains. Clay gypsum is a natural formation of fine-grained crystalline gypsum, evenly mixed with clay or loam. The amount of gypsum ranges from 5 to 65%. The uniform distribution of clay particles in the gypsum matrix is due to the genesis of this sedimentary rock. Of interest are modifications of clay gypsum, including those using lime to produce lime-gypsum binder. The possibility of using quicklime allows us to solve the problem of heat treatment of clay gypsum in order to dehydrate the rock to the semi-aqueous state of gypsum. Also, lime contained in the material modifies the structure of clay, increasing the surface energy of clay particles. The purpose of the research was to develop a basic formulation for dry plaster plaster mixtures based on lime-clay-gypsum binder and evaluate the possibility of increasing its water resistance. As a result of the research, the optimal consumption of quicklime was established, equal to 48%, it was found that the specific surface of quartz sand significantly affects the softening coefficient of the material, and also the basics of the methodology for selecting the composition of the plaster mixture were developed and a nomogram was formed for predicting the properties of the plaster mixture and selecting recipe parameters. It has also been established that the temperature generated when mixing both the binder and the plaster mixture with water fully corresponds to the conditions for dehydration of the clay-gypsum component of the composite binder. Plaster mixtures based on lime-clay-gypsum binder and finely ground quartz sand can be used for interior decoration of dry rooms and rooms with relative humidity up to 75%.