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.
- ACI RAP Bulletin 12, Concrete Repair by Shotcrete Application
- Austin S., Sprayed Concrete Technology, The Proceedings of the ACI/SCA International Conference on Sprayed Concrete/Shotcrete, ISBN 0-203-78536-3, Taylor & Francis e-Library, 2005;
- European Specification For Sprayed Concrete – Guidelines for specifiers and contractors, EFNARC, 1999;
- БДС EN 14487-2:2007 Торкретбетон. Част 2: Изпълнение;
- БДС EN 14488-1:2006 Изпитване на торкретбетон. Част 1: Вземане на проби от бетонна смес и втвърден бетон;
- Thomas А., Sprayed concrete lined tunnels, ISBN 0-203- 02899-6, Taylor & Francis, 2009;
- F. Rouquerol, J. Rouquerol, K. S. W. Sing, Adsorption by Powders and Porous Solids, Academic Press, London, UK, 1999;
- S. Lowell, J. Shields, M. A. Thomas, M. Thommes, Characterization of Porous Solids and Powders: Surface Area, Pore Size and Density, Springer, The Netherlands, 2004.
- Barrett, E.P.; L.G. Joyner, P.P. Halenda (1951). "The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations form Nitrogen Isotherms". J. Am. Chem. Soc. 73 (1): 373–380