Open AccessPeculiarities of hardening of an astringent system based on orthophosphoric acid and serpentine with an admixture of magnesite
Author(s) -
А. А. Орлов,
Т. Н. Черных,
В. В. Зимич
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/962/2/022005
Subject(s) - magnesite , brucite , hardening (computing) , materials science , carbonation , magnesium , chemistry , chemical engineering , nuclear chemistry , metallurgy , composite material , layer (electronics) , engineering
The paper considers peculiarities of hardening of the non-burnt binder system – orthophosphoric acid – natural serpentine with an admixture of magnesite and brucite. The samples were hardened according to the regime: pre-soaking (55 °C, 40 minutes), which ensures the preservation of the viscous-plastic state of the composition during the carbon dioxide evolution, followed by isothermal aging (80 °C, 24 hours). Strength increases with raising the amount of reacted serpentine and decreases with raising the volume of the released gas. The presence of trisubstituted magnesium phosphate, responsible for the strength, was established. In the solidified system, amorphous silica and unreacted serpentine, brucite and magnesite were found. The strength can be controlled by changing the specific surface of serpentine and the ratio between orthophosphoric acid and serpentine. It is possible to obtain a stone with strength of up to 40 MPa on the basis of serpentine and orthophosphoric acid after 1 day of hardening, with a specific surface of serpentine 4000 cm 2 /g and an amount of orthophosphoric acid of 25 % of the mass of serpentine.