Optimizing Flexural Strength of Concrete Fc’ 14,5 MPa Using Acetylene Welding Carbide Waste

Replacing the main material using unused materials such as hazardous waste can be utilized in concrete innovation. One of the hazardous wastes that can utilize the waste generated from the acetylene welding process. The waste has hardening properties when exposed to water. Its properties are almost the same as cement can replace or add part of the cement mixture. Conducted this research was to determine the effect of using carbide waste from the acetylene welding process on the flexural strength of concrete. The experimental method is carried out by making test objects in the laboratory. The proportions of waste added were 7%, 10%, and 12% by weight of cement. The test object used is in the form of a beam with dimensions of 60 cm x 15 cm x 15 cm. The planned initial quality is concrete F'c 14.5 MPa (K175). The flexural strength test was carried out at the age of 27 days of concrete. From the results of the research carried out, it is found that the use of carbide waste from the acetylene welding process has not been able to improve the quality of concrete significantly. The highest flexural strength was obtained from waste at 7%, with a flexural strength value of 9.692 Mpa. So from these results, it can be used as a reference in the utilization of carbide waste from the acetylene welding process.

Problems of customs control over the movement of hazardous waste across the customs border of the Eurasian Economic Union

Hazardous waste is a trigger of the environmental crisis, especially at the stage of increasing production and consumption of goods, leading to a significant increase in industrial waste and its movement across customs borders. The cross-border movement of hazardous waste is controlled by the state, customs authorities are entrusted with the tasks of protecting national security, human life and health, animal and plant life, the environment, including protection against the illegal import of hazardous waste. The transboundary movement of hazardous wastes is carried out within the framework of the permissive procedure. Such a unified licensing procedure has also been adopted in the EAEU with respect to the import into the customs territory, transit, export from the customs territory of dangerous wastes. This procedure assumes that the declarant submits to an official of the authorized body a license of the Ministry of Industry and Trade of the Russian Federation or a permit for the transboundary movement of hazardous waste of the Federal Service for Supervision of Environmental Management. However, despite the efforts of the international community in the fight against hazardous waste, the dynamics of illegal movement of certain types of waste continues to grow, which indicates the existence of a number of unresolved problems. In the course of the study, the conceptual and categorical apparatus in the field of hazardous waste is analyzed, the main provisions of the procedure for moving this category of goods across the customs border of the EAEU are considered. The basis for national legislation in terms of the conceptual apparatus and regulation of the transboundary movement of hazardous wastes through the customs territory of the EAEU is the norms of international law, while a comparative analysis confirms the ambiguity of their recognition and classification in the EAEU member states. The analysis of the dynamics of the movement of hazardous waste, including used pneumatic tires and tires, showed that every year the problems of environmental protection become more acute. As a result of the study, specific problems in the field of transboundary movement of hazardous wastes were identified and recommendations for their solution were given.

Immobilization of Hazardous Wastes on One-Part Blast Furnace Slag-Based Geopolymers

The immobilization of hazardous wastes in ordinary Portland cement (OPC)-based materials has been widely studied and implemented. OPC-based materials have a high carbon footprint associated with their production and geopolymer materials are a sustainable and eco-friendly alternative. Therefore, this work aimed to immobilize two hazardous industrial wastes: copper wastewater sludge and phosphogypsum in one-part geopolymer materials. For that purpose, the precursor was partially substituted by these wastes (5, 10 and 20 wt.%) in the formulations. The geopolymer fresh and hardened state properties were evaluated, and the immobilisation of pollutants was determined through leaching tests. In phosphogypsum pastes (PG5, PG10 and PG20) it was observed that the compressive strength decreased with the increase in its amount, varying between 67 MPa and 19 MPa. In copper sludge pastes, the compressive strength of the specimens (CWS5 and CWS10) reached ~50 MPa. The mortars, MPG10 and MCWSs10, had compressive strengths of 13 MPa and 21 MPa, respectively. Leaching tests showed that pastes and mortars immobilise the hazardous species of the wastes, except for As from copper sludge, whose the best result was found in the compact paste (CWSs10) that leached 2 mg/kg of As. Results suggest that optimized compositions are suitable for the construction sector.