Expanded clay concrete differs from heavy-weight concrete not only by the composition and performance properties, but also by modes of chemical interactions between the components. So, not the primary problem of reinforcement corrosion in heavy-weight concrete under the normal conditions and the correct protective layer, becomes in the major problem in expanded clay concrete. The issue of reinforcement corrosion in expanded clay concrete is considered in this article. The studies on the effect of different compositions on the corrosiveness were conducted. Researchers have proposed various options for expanded clay concrete reinforcement protection from the environmental impact, including those through a variety of chemically active additives. According to the data obtained by experimenting, the diagrams of corroded area size dependence on various factors were presented.The results of the studies conducted are the recommended design and technological measures for the reinforcement protection against corrosion in various fine aggregate-based (natural sand, ash and dry hydroremoval) light-weight expanded clay concrete. Thus, the minimum concrete protective cover for main and distribution reinforcement of external walls must be at least 25 mm. It is necessary to inject additives -reinforcement corrosion inhibitors (sodium nitrite, sodium tetraborate) to the concrete composition. The consumption of cement, and hence, the cement paste content of concrete mixture must be not lower than 220 kg/m 3 , and under the application of the active dry fly ash removal À200 kg/m 3 .

For building in subsided areas of abandoned coal mines and open pits on soils damaged by anthropogenic impact and mining operations, it is proposed to base buildings and structures on a three-layer slab founda- tion including: a solid reinforced concrete foundation slab, a sub-ballast of ground overburden burnt rocks and a rock concrete compensation slab lo- cated between them. During subsidence of damaged soils, the rock concrete compensation slab, collapsing and increasing in volume, fills the sinkhole lens under the building with pieces of rock concrete, protecting the rein- forced concrete foundation slab from destruction. It was experimentally es- tablished that for the production of rock concrete compensation slabs, ce- ment rock concrete with aggregate of ground burnt rocks with a coarse frac- tion (–20+10) mm and a fine fraction (−0.63) mm should be used; the ratio of the percentage mass fraction of coarse and fine fractions being 25/75 and 50/50 and the cement-water mass ratio C:W being 1:0.5. The reinforced concrete compensation slabs of the recommended composition can take a design load of up to 9-11 MPa in dry and up to 8-9 MPa in water-saturated conditions. The use of ground overburden burnt rocks for the manufacture of rock concrete compensation slabs and sub-ballast will allow utilizing overburden burnt dumps and improving the environmental situation when building in subsided areas of abandoned mining enterprises.

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The issues of the modification of a binder in structural cement concrete for mine and underground construction with wastes of chemical enterprises are considered in the article. Hundreds of tons of waste are generated annually at chemical enterprises of the Russian Federation, polluting the environment and requiring their disposal. The performed studies deal with the improvement of physical and mechanical properties of a cement binder with a dispersed manganese sludge modifier, which is a waste product of ammonia or methanol production, for its use in mine and underground construction. As a result of the studies performed, it was found that the addition of dispersed sludge with manganese oxide in an amount of 4% of the cement mass to a cement binder leads to the activation of the cement hydration process, while the rate of development of the plastic strength of the cement stone structure increases, the period of its structure formation reduces and the compressive cement stone strength increases by 17-18%, which makes it possible to reduce the cement content in structural concrete by 8.8-10.0% while maintaining its strength, reducing the cost of mine and underground structures and, as a result, reducing the cost of mining.

Угляница А.В. -постановка исследовательской задачи; научный менеджмент; обзор соответствующей литературы; концептуализация исследования; написание текста, сбор и анализ данных; обзор соответствующей литературы; выводы; написание текста.Все авторы прочитали и одобрили окончательный вариант рукописи.