| Summary: | Introduction. Waste concrete is one of the main heavy construction waste having good recycling prospects with regard
to rational nature management related to reducing the consumption of natural resources. However, the widespread introduction
of waste concrete is hindered on the one hand by the variety of compositions and structures of recycled scrap, and on the other
hand by the lack of quantitative criteria to choose the most rational area of its use (a binder component, coarse and fine aggregate,
finely dispersed filler, etc.). Materials and methods. Case studies of experimental powders obtained by mechanical grinding from
the concrete scrap of internal wall panels and floor slabs (heavy concrete) and external wall panels (light concrete) of a five-storey
residential panel house built in 1979 in the Obozersky village, Arkhangelsk region, demonstrated the possibility of choosing the
optimal secondary use of waste concrete fractions featuring residual compressive strength. The indicators of residual strength,
grindability and contraction of mineral powders were used as optimization criteria. Results and discussions. The applicability of
the mathematical model for calculating the raw material grindability index is shown. A criterion for grinding equipment selection
is proposed to obtain powders with an extended active surface. Conclusions. Powders obtained from the fraction of waste light
concrete featuring low strength properties and grindability by mechanical grinding to a specific surface area comparable to that of
Portland cement used and having a higher value of contraction can be rationally used as a composite binder component. Concrete
scrap fractions featuring by higher grindability and strength properties are optimally suited for crushed aggregate preparation in
the concrete composite production process.
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