Structural and Thermal Insulation Materials Based on High-Strength Anhydrite Binder

Abstract

The properties of a structural and thermal insulation composition based on a high-strength anhydrite binder based on fluoroanhydrite and expanded perlite sand have been studied. Fluoroanhydrite is a waste product of hydrofluoric acid and it is an eco-friendly material. Due to the processing of man-made anhydrite, it is possible to reduce the harm caused to nature in places of raw materials dumps, as well as significantly reduce the cost of producing new construction materials. The use of anhydrite compounds in the manufacture of products is limited with low speed setting and hardening. To activate the structure formation of the anhydrite binder, 3% aqueous solution of sodium phosphate Na3PO4 was used. Expanded perlite sand was used as an ultralight aggregate. As a result of the experiments, it was possible to obtain a lightweight composition possessing high strength. Studies of the microstructure and X-ray microanalysis showed new formations appearing in the interfacial zone at the border of the anhydrite binder and expanded perlite, which is confirmed by the results of the infrared spectroscopy. Also there has been noted the consolidation of the anhydrite binder structure by nanodispersed structures formed in the intercrystallite pores of the anhydrite binder. The developed composition can serve as a cheap substitute for gypsum in the production of warm plaster, gypsum boards, architectural elements by molding, tongue-and-groove slabs, wall blocks, as well as wall thermal insulation during frame construction, including for filling hollow masonry.

Fluoro​an​hydrite Compositions Plasticized by Polycarboxylate Esters

“…To determine the physico-mechanical parameters, the compositions were prepared in the following order: fluoroanhydrite was tempered with an aqueous solution containing 2-3% activator of hydration of sodium phosphate (Yakovlev et al, 2018) and 2% DC-5 superplasticizer. In lightweight formulations, expanded perlite was added into the finished fluoroanhydrite dough to provide better adhesion of the aggregate surface to the binder matrix (Yakovlev et al, 2019b).…”

Low energy synthesis of anhydrite cement from waste lime mud

“…Anhydrite cement is a promising material in the production of dry building mixes, including self‐leveling mixes, 10 due to its heat‐insulating and sound‐proofing properties, both of which are superior to those of mixes based on Portland cement 11 . A promising material for the production of anhydrite cement is synthetic gypsum derived from a carbonate component and sulfuric acid 12,13 .…”