Innovative method for disposal of waste of monolithic building structures
Authors:   St. Petersburg State University of Architecture and Civil Engineering, REPIN Sergey , AFANASYEV Alexander ,   St. Petersburg Mining University, DOBROMIROV Viktor ,   St. Petersburg State University of Architecture and Civil Engineering, BARSUKOV Vladislav ,   St. Petersburg State University of Architecture and Civil Engineering
Published: December 2023

Introduction. During the reconstruction and technical re-equipment of various mining facilities, there is a need for the processing of concrete and reinforced concrete products that require environmental protection. The article analyzes innovative methods of destruction of hard rocks based on the use of electrohydraulic effect. The possibility of their use as an alternative environmentally friendly method of recycling reinforced concrete products is evaluated. A schematic diagram of an electrohydraulic installation for use for these purposes is presented. Based on the analysis of the mechanism of destruction of concrete and reinforced concrete products, the main electrical parameters that ensure the effectiveness of its application are substantiated. An assessment of the effectiveness of the implementation of the proposed technology in the process of recycling reinforced concrete structures was carried out. Materials and methods. After the main dismantling activities, the issue of removal and utilization of construction waste is solved, which requires its shredding. When using electrohydraulic technology for demolition of reinforced concrete, this production process includes: prior to processing – segmentation of structures by means of excavator hydraulic shears into fragments up to 1 m3 in size; placing them on the support grid of the EGU bath filled with water; grounding of the fittings; installation of working arresters in the bath and energizing of the EGU; after treatment – removal of the reinforcement cleaned from concrete from the bathtub; removal of the basket with concrete rubble from the EGU; storage of treatment products; installation of the released basket in place. Results and discussion. As a result of the research the organization of the production process of recycling of reinforced concrete fragments of building structure during their disposal using the technology of electrohydraulic crushing of concrete blocks at the site of their dismantling is proposed. Rational values of parameters of the organization of the destruction process in the EGU have been established: the distance from the arrester axis to the point of reinforced concrete blocks in the liquid volume; capacitance of the capacitor block; voltage at the moment of breakdown; inductance of the discharge circuit; cyclic frequency of oscillations. When using water as a working fluid, it is reasonable to vary the frequency of discharge pulses within 0.5...2.0 Hz. It has been established that the productivity of the single-electrode unit at the destruction of reinforced concrete to the final coarseness of 20 mm reaches 100 kg/h at a specific energy consumption of 120 kW/t. The use of 4-electrode EGU can ensure the crushing of one ton of reinforced concrete to a fraction of 20 mm in 2.5 hours. Increasing the overall environmental friendliness of the whole process of utilization of reinforced concrete products can be ensured by replacing the mechanical destruction of products by hydraulic shears with dust-free destruction by means of generation of a high-voltage current pulse by an electrode in a borehole filled with water. Сonclusion. According to the results of the conducted research, it is clearly seen that the proposed technology of electrohydraulic crushing of concrete blocks is a promising solution for effective utilization of reinforced concrete structures in the mining industry. Organization of the production process of recycling at the site of dismantling using this technology not only reduces the cost of transportation of materials, but also contributes to reducing the negative impact on the environment. The established rational parameters of the destruction process in the electrohydraulic unit provide the basis for optimization of the technology, which, in turn, provides precise regulation of the recycling process and increases its efficiency. Thus, the research results indicate that the proposed electrohydraulic shredding technology is a promising direction for the development of effective and environmentally friendly methods of construction waste utilization.