Urban Mining - Design Documentation

Raw materials for construction and industrial uses are becoming increasingly expensive. It is predicted that there will come a time when it is cheaper to recycle and reuse material that has already entered the manufacturing process than to mine new material from the earth. This is already the case in the steel industry, where scrap metal is easily melted down and recast. However, many potentially valuable waste materials are not currently recycled. Urban mining is the practice of reusing these unutilized materials instead of throwing them away to preserve their embodied energy.

Volvo Construction Equipment challenged a team of students from Stanford University in the United States of America and the Blekinge Technical University in Sweden to develop a new technology in the field of urban mining that could be added to their product line. Volvo’s effort to enable more large-scale recycling is in line with its core value of environmental care.
To better understand the problem, the Stanford and BTH teams conducted interviews and site visits to businesses in the four urban waste streams: construction and demolition (C&D), municipal, electronic, and rubber. It was found that the C&D industry accounts for the vast majority of all urban waste. There are several relatively new products, such as portable concrete crushers and onsite sorters, which allow contractors to reuse materials on a construction job site instead of trucking them to a landfill, which is costly. Off-hauling C&D waste from a demolition site typically accounts for half of the total budget of a demolition project. However, after more interviews were conducted, it became clear that another problem was in play: lack of job site space.

Often, construction sites are limited by their footprint area, especially in urban areas. Currently, onsite reuse operations, such as crushing concrete for use as infill, take up large areas. Through prototyping and user-feedback, a system to effectively store large volumes of aggregate material in a tight footprint was designed.