FIELD: chemistry.
SUBSTANCE: invention relates to construction materials, and specifically to additives used in production of gypsum binding materials, dry construction mixtures, mortar and concrete articles based on said binding materials. The complex additive for modifying gypsum binding materials, dry construction mixtures, mortar and concrete based on said binding materials, containing a mineral component based on calcium sulphate, a plasticiser, a hardening and setting time regulator, contains said mineral component in form of crude ground gypsum, plasticiser in form of Sika Viscj Crete 225 powder Vp or Melflux 5581F, the hardening and setting time regulator in form of calcium gluconate and additionally contains a water repellent - calcium polymethyl siliconate and an antifoaming agent - Axilat DE 770, where said components are in the following ratio in wt %: said mineral component 64.0-78.0, said plasticiser 15.0-20.0, said water repellent 4.8-8.6, said antifoaming agent 0.2-0.4, said hardening and setting time regulator 2.0-7.0.
EFFECT: high strength and water resistance of the obtained gypsum binding materials, mortar and concrete based on said binding materials, reduced shrinkage of the hardened material, low fluidity of the gypsum suspensions.
7 ex, 1 tbl
