Development of Eco-Friendly Deconstruction Technologies for Recycling Construction Waste

Abstract

Recently, the intended use and required performance of buildings are rapidly changing with advances in scientific technology and globalization. Furthermore, given the population growth in semi-developed and developing countries, economic growth, increasing waste, and increasing amounts of energy consumption, the industry requires the development of efficient methods to deconstruct old buildings by reducing waste and saving as much energy as possible during periods of urban redevelopment and maintenance. In general, either an ordinary breaker or a hydraulic breaker is used to deconstruct reinforced concrete buildings. This deconstruction method has the ability to shorten the construction period compared to the other methods, but it is difficult to separate the debris that gets mixed when the deconstruction is completed, as it is a rough construction method that uses large equipment. This study develops a technology that can be used to selectively heat, separate, and deconstruct the steel reinforcement inside reinforced concrete, treating the reinforcement as a conductive resistor and applying high-frequency induction heating to the reinforced concrete structure. Specifically, this study verifies the temperature characteristics of deformed bars inside reinforced concrete, the occurrence of cracks due to thermal fracture of the deformed bars, and chemical and physical weakening of concrete by thermal conduction on the surface of steel reinforcement using the high-frequency induction heating technology. Furthermore, this study considers the extent of concrete weakening in the heating range of appropriate energy and carries out a technical review of the stages that would be actually applied. This technology involves low noise and low pollution levels, and it increases the collection rate of steel reinforcement inside separated reinforced concrete members and the recycling rate of construction wastes; thus, its use is expected to reduce the energy consumption by minimizing secondary processing.