For concrete structures that are demolished or refurbished, concrete crushing is increasingly being used to process concrete. Sometimes concrete waste is landfilled, but for recycling, crushing has several benefits, making it a more attractive method in the 21st century, when environmental ecology, environmental legislation and the desire to reduce construction costs are a priority.
The concrete aggregate collected from the demolition sites is discharged through a crushing machine – a crusher. Only unmodified concrete is used in the crusher, and there must be no waste – wood, paper and other such materials. Metals, such as reinforcement, are accepted because they can be removed with magnets and other sorting devices and melt so that they can be recycled elsewhere. The pieces of the remaining aggregates are sized in size.