Improve the quality of construction and demolition waste by separation techniques

Abstract

Each year about 16 million tons of construction and demolition waste (CDW) is produced in the Netherlands, which locally is the largest solid waste stream. Currently, about 90% (by weight) of construction and demolition waste is being reused. However, most of it is reused in road foundations, and embankments, therefore, construction and demolition waste is still recycled in relatively low technical applications. In order to recycle CDW at a high technical level, the two main materials from CDW—concrete rubble and brick (masonry) rubble—should be recycled/reused in the concrete industry and in the brick industry respectively, and proper quality control is an important step to ensure qualified products without environmental risks. This chapter investigates effective separation techniques used to improve the quality of CDW, based on differences in physical properties and chemical compositions between concrete/mortar and brick. Both dry and wet separation techniques are used to obtain concentrates of concrete/mortar rubble, and brick rubble. The results show that magnetic separation, jigging, spiral separation, and color separation can be successfully applied for treating construction and demolition waste, and clean products obtained finally are satisfactory.