An innovative approach for repairing of corroded reinforced concrete industrial structures in aggressive environment by high-tech hybrid reinforced sprayed concrete with capillary crystalline admixture


Solvay Sodi JSC, Devnya, Bulgaria, is the biggest calcite soda production plant in Europe. It is built in 1974 and it works in three-shift production regime up to present days. The exploitation environment is highly influenced by numerous factors, acting corrosively on main reinforced concrete structures – active atmospheric processes (in continental type moderate climate), sea water born chloride-aerosols, as well chemical attack caused by carbon dioxide and nitric acid, presented in the air in form of evaporation. The most reinforced concrete structures need urgent remedial measures to restore the load-bearing capacity of its components.
The “light soda” silos are reinforced concrete facilities (cylindrical shells) which repair has to be executed during continuous production process. The options for repair of these structures and restoration of their load bearing ability by specially designed innovative high-tech hybrid reinforced sprayed concrete, containing capillary crystalline admixture, are discussed in the report.
The in-situ tests and wide-range comparative studies are carried out, covering basic physical and mechanical structural characteristics of the proposed sprayed concrete for wet spraying and another one – based on proportioned dry ready mix.
The original scientific results concerning strength-deformation properties, phase composition and structure of hardened sprayed concrete, directly related to the durability in aggressive environment, are obtained by X-ray diffraction (XRD), differential thermal analysis (DTA), mercury porosimetry, low temperature gas adsorption (BET-method) and computer X-ray tomography.
The static and dynamic analysis of the structure is performed using the test results obtained and the fully specified engineering solution
has been presented to restore the load-bearing capacity of the structures with a guaranteed service life of at least 50 years.



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