Geoecological analysis of impacts of the use of plastic waste in road construction on the geological environment

Abstract

Currently, society and industry are developing at a rapid pace, and an increas- ingly serious problem of the modern world is environmental pollution, requiring recycling and reuse wastes. Modern technologies in the field of road construction involve the use of polymeric materials obtained from waste recycling. Almost nothing is known about soil contamination by plastic in general and the destruction of roads in particular; probably because of lack of awareness and absence of standard methods for quantifying plastic components in soil. The contemporary data suggest that flow of plastic has already reached a value similar to that found for other contaminants, such as heavy metals. In particular, migration is observed for plastic microparticles, but so far, their effect on groundwater has not been studied. Therefore, additional research is urgently needed to shed more light on the fate and impact of these persistent materials in the terrestrial environment. The purpose of the study was a geoecological analysis of the risks of using polymer waste in construction of roads to the geological environment. To ensure environmental safety in the implementation of technologies for the utilization of polymer waste, it is necessary to take into account their chemical composition, the ability to form hazardous products in increasing temperature, hazard class, physical and chemical properties. We propose criteria for assessing the possibility of recycling polymer waste in road construction, namely for the manufacture of asphalt concrete. According to the pro- posed overall criterion, taking into account not only technical and economic indicators, but also the environmental component, we can recommend the use of HDPE and LDPE, as well as PP for use in road construction. Taking into account the total criterion, we recom- mend using HDPE, LDPE as the most acceptable waste for road construction,, as well as PP. The technological scheme should include the collection, sorting of these plastics, as those that do not contain hazardous chemicals. Temperature conditions for manufacturing asphalt involve heating and converting the components into the liquid phase for uniform mixing of the entire composite. Under those temperature conditions, chemical compounds that are harmful to the environment and humans would not be created. The possibility to substitute part of the bitumen, to obtain asphalt concrete with high performance, increased service life shows the cost-effectiveness of using these groups of polymer waste in the technology of manufacturing asphalt concrete. The lack of regulatory framework and technical standards for working with polymers for paving brings the problem of plastic roads to the legislative level.