MATERIAL TO BE USED AS CONCRETE ADDITIVE Russian patent published in 2015 - IPC C04B24/38 C04B28/02 C04B111/20 

FIELD: chemistry.

SUBSTANCE: invention relates to an admixture for a cementitious composition comprising microfibrillar cellulose and/or a derivative thereof. The invention also relates to a method of manufacturing said admixture and to the use of the microfibrillar cellulose and/or a derivative thereof in the concrete admixture. The invention further relates to a cementitious composition comprising said admixture and methods of manufacture and use thereof. A cement admixture, wherein the admixture comprises microfibrillar cellulose; and/or a derivative thereof; and/or labile chemically modified cellulose pulp or cellulose raw material which forms microfibrillar cellulose during the use of the admixture; and optionally water, wherein the microfibrillar cellulose is obtained from raw material comprising plant material. A method of manufacturing a cement admixture comprising providing microfibrillar cellulose and/or a derivative thereof, mixing together said microfibrillar cellulose and/or a derivative thereof, and optionally water, adding at least one plasticiser and/or dispersing agent prior to, during or after providing microfibrillar cellulose to obtain said admixture. The invention is expanded in dependent claims.

EFFECT: paste thixotrophy is increased, water bleeding diminished and concrete durability properties are increased.

22 cl, 16 dwg, 7 tbl