Leonovich S.N., Sviridov D.V., Shchukin G.L., Belanovich A.L., Karpushenko S.A., Savenko V.P.

SERGEI N. LEONOVICH, Doctor of Technical Sciences, Professor, Belarusian National Technical University, Minsk. 65 Independence Ave., Minsk, Republic of Belarus, 220013, e-mail: sleonovich@mail.ru. 
DMITRY SVIRIDOV, Doctor of Chemical Sciences, е-mail: sviridov@bsu.by, 
GEORGY SHCHUKIN, Candidate of Chemics, e-mail: shchukin@bsu.by, 
ANATOLY BELANOVICH, Candidate of Chemics, e-mail: lab508@mail.ru,
SERGEI KARPUSHENKOV, Candidate of Chemics, e-mail: lab508@mail.ru, 
VICTOR SAVENKO, Senior Researcher, e-mail: lab508@mail.ru.
Belarusian State University, Minsk. 4 Independence Ave., Minsk, Republic of Belarus, 220030.

Compensation of shrinkage behaviour of foam concrete

It has been established that producing a low-shrinkable foam concrete with the density of 200–400 kg/m3 from the cement mix containing the dehydrated sodium citrate and the expending sulfoaluminate modifier ESAM is promising. The effect of the compensation of shrinkage reveals itself due to the synthesis of foam-cement structures of the low-main hydrosilicates which grow over with gel materials generated by the interaction of the cement components with sodium citrate and ESAM which forms a new block structure. Such block structures show resistance to shrinkable phenomena when a foam-cement framework transforms to an elastic state. The process of the hardening of the foam concrete structure is withstood by a migration of water under the effect of the temperature gradient which results in destructive phenomena, moist shrinkage, swelling of steam partitions owing to vapor condensation, and etc. Determining destructive processes in the production of foam concrete are heat and mass exchange in moist porous bodies as well as the tensions caused by the temperature expansion of the material. To obtain a uniform distribution of thermal streams when drying foam concrete, a simultaneous heating of the entire of its volume is required. In the authors’ opinion, it may be achieved with the help of microwave radiation which secures a uniform drying without shrinkage and noticeable cracks. The additional processing they propose makes it possible to improve considerably the strength and durability of foam concrete. 

Key words: foam concrete, cement, foam-mass, shrinkage, sodium citrate.

REFERENCES

2. Dvorkin L.I., Dvorkin O.L. Construction materials science. Moscow, Infra-Inzheneriya Publ., 2013. 832 p. (in Russ.) [Dvorkin L.I., Dvorkin O.L. Stroitel'noe materialovedenie. M.: Infra-Inzhenerija, 2013. 832 s.].

3. Krivitsky M.J., Levin N.I., Makarychev V.V. Cell concrete. M., Stroiizdat Publ., 1972, 137 p. (in Russ.) [Krivickij M.Ja., Levin N.I., Makarichev V.V. Jacheistye betony (tehnologija, svojstva i konstrukcii). M.: Strojizdat, 1972. 137 s.].

4. Kudyakov A.I., Kiselev D.A., Shirshov V.I. Management of structure and quality of foam concrete. Design and construction in Siberia. 2005;4: 29-30. (in Russ.) [Kudjakov A.I., Kiselev D.A., Shirshov V.I. Upravlenie strukturoj i kachestvom penobetona // Proektirovanie i stroitel'stvo v Sibiri. 2005. № 4. S. 29-30].

5. Leonovich S.N., Sviridov D.V., Belanovich A.L., et al. Prolongation of Working Life of Mortar Mixes. Structural materials. 2012;10:74-77. (in Russ.) [Leonovich S.N., Sviridov D.V., Belanovich A.L. i dr. Prodlenie sroka godnosti rastvornyh smesej // Stroitel'nye materialy. 2012. № 10. S. 74–77].

6. Mamontov A.V., Nefedov V.N., Nazarov I.V. et al. Microwave technologies: monograph. Moscow, Scientific Research Institute, 2008, 308 p. (in Russ.) [Mamontov A.V., Nefedov V.N., Nazarov I.V. i dr. Mikrovolnovye tehnologii: monografija. M.: GNU NII PMT, 2008. 308 s.].

7. Mechai A.A., Baranovskaya E.I. Formation of composition and structure of products hydrosilicate hardening in the presence of sulfomineral additives. Cement and its Application. 2010;5:128–133. (in Russ.) [Mechaj A.A., Baranovskaja E.I. Formirovanie sostava i struktury produktov gidrosilikatnogo tverdenija v prisutstvii sul'fomineral'nyh dobavok // Cement i ego primenenie. 2010. № 5. S. 128–133].

8. Protko N.S., Mechay A.A. Expanding sulfoaluminate modifier for compensating the shrinkage strain of concretes and solutions. The problems of modern concrete and reinforced concrete: proc. International symposium, vol. 2. Minsk, 2007, р. 255–271. (in Russ.) [Prot'ko, N.S. Mechaj A.A. Rasshirjajushhij sul'foaljuminatnyj modifikator dlja kompensacii usadochnyh deformacij betonov i rastvorov // Problemy sovremennogo betona i zhelezobetona: tr. mezhdunar. simpoziuma, ch. 2. Minsk, 2007. S. 255–271].

9. Ruzhensky S.R., Portik A.A., Savinih A.V. Everything about foam. St. Petersburg, Stroybeton Publ., 2006, 630 p. (in Russ.) [Ruzhenskij S.R., Portik A.A, Savinyh A.V. Vse o penobetone. SPb.: Stroj Beton, 2006. 630 s.].

10.Savenko V.P., Shchukin G.L., Leonovich S.N. et al. Method of obtaining the hardener for the concretes and the mortars. Patent N 18077, Belorussia. Published in Bull. of Inventions, 2012, N 2. (in Russ.) [Savenko V.P., Shhukin G.L., Leonovich S.N. i dr. Sposob poluchenija uskoritelja tverdenija dlja betonov i stroitel'nyh rastvorov: Pat. № 18077 Respublika Belarus'. Opubl. BI № 2, 2012].

11.Sakharov G.L. Complex assessment of crack resistance of cellular concrete. Concrete and Reinforced Concrete. 1990;10:39-41. (in Russ.) [Saharov G.L. Kompleksnaja ocenka treshhinostojkosti jacheistyh betonov // Beton i zhelezobeton. 1990. № 10. S. 39–41].

12.Kharkhadin A.N. Structural topology of foam concrete. Construction. 2005; 2:18–25. (in Russ.) [Harhadin A.N. Strukturnaja topologija penobetona // Izv. Vuzov. Stroitel'stvo. 2005. № 2. S. 18–25].

13.Chindaprasirt P., Rattanasak U. Shrinkage behavior of structural foam lightweight concret containing glycol compounds and fly ash. Materials & Design. 2011(32)2:723-727.

14.Stark J. Recent advances in the field of cement hydration and microstructure analysis. Cement and Concrete research. 2011(41)7:666-678.