Aerated dry mix concrete for remote northern territories

Строительные изделия и конструкционные материалы

The study results on aerated concrete based on imported long-term storage clinker and mineral additives for northern remote construction sites are presented here. The relevance of the research is due to the need for cement composites of stable quality to install enclosing structures at remote northern construction sites. It is impossible to ensure stable quality and safety of construction objects using imported cement due to a significant decrease in its activity during transportation and long-term storage. This problem is shown to be solved by organizing the production of aerated concrete from imported Portland cement clinker using a mechano-chemical technological platform, including: scientific substantiation of the components’ choice, mechanical or mechano-chemical activation of clinker by joint grinding with additives and obtaining a dry mixture, preparing aerated concrete mixture and hardening aerated concrete in molded products. Modern physicochemical methods for studying cement compositions are used in this scientific work. Ensuring the required characteristics of aerated concrete on imported Portland cement clinker is provided by introducing activated mineral additives of wollastonite and diopside, which have a chemical affinity with cement minerals and hydrosilicates. It was found that the activity of the binder increased by 30 % and 59 %, respectively when 7 % wollastonite and diopside with a specific surface area of 309 and 323 m2/kg were added to cement from imported clinker for long-term storage. At the same time, the initial activity of cement (43 MPa) is restored even with the 2 % content of diopside of a specific surface area of 323 m2/kg. An increase in the activity of cement from imported clinker was explained by the formation of an additional amount of low-basic hydrosilicates and a decrease in stone porosity. Aerated concrete from cement, based on imported clinker, has a homogeneous structure of evenly distributed pores with an average diameter of 6.81 microns, which provides a 10–15 % increase in strength with a compression variability coefficient of 5.4. The obtained aerated concrete had the strength of B2 class, F75 grade frost resistance and thermal conductivity coefficient of 0.14–0.15 W/(m∙oC). The developed aerated concrete and the technology of its preparation from imported Portland cement clinker are intended for the construction of buildings in the remote northern territories.