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The review of foreign studies devoted to the utilization of polymeric composite materials (PCM) by the solvolysis method is presented. It has been established on the basis of this that two groups of technologies predominate: directed to fiber extraction by destruction of the organic matrix and based on partial destruction of individual bonds while preserving valuable matrix components. The results of experimental studies on the selection of reagents for the recovery of carbon fiber from phenol formaldehyde PCM are presented. The characteristics of the change in the properties of the secondary fiber on the basis of a visual assessment are given, showing the appearance of roughness and irregularities in the fiber swirl and a significant decrease in their thickness. The results of research on fine-dispersed reinforcement of concrete with secondary carbon fiber, which showed an increase in flexural strength by 3–8 %, are described. The problem of dispersion of secondary carbon fiber during its introduction into concrete is considered.

The results of studying the structure formation features of silicate bricks obtained with the use of solid waste produced by JSC "Berezniki soda plant" are presented in this article. Various samples, such as sludge from the "closed" sump with a moisture content of 5 %, sludge from the open sump surface with a moisture content of 35 %, moistened sludge from the open sump with a moisture content of 70 %, were taken from the sludge collectors for the research. It was established the building lime meeting the requirements of GOST 9179 can be received by means of heat treatment at 950 °C of the dehydrated slime selected from the closed settler. By results of silicate brick samples forming parameters and their structure optimization it was found that the use of lime from soda production solid waste as part of lime-silica autoclave hardening binder allows to obtain silicate bricks samples, characterized by the strength grade M200. Samples microstructure studies obtained using the methods of electron microscopic and x-ray phase analysis showed that silicate samples produced with the use of soda production waste are characterized by a cementing substance heterogeneous structure and an insufficient number of tobermorite group low-basic calcium hydrosilicates formed during autoclaving. This is due to the waste material composition, namely the presence of reactive-passive components and impurities. Increasing the structural strength of samples made with the use of soda production wastes is possible due to raising the lime-silica binder specific surface area and the binder modification with fine mineral additives.