A California-based company has developed a new technology that repurposes excavated waste on building sites into building material, eliminating the problem of waste disposal.

Watershed Materials' onsite pop-up plant repurposes excavated material right at the job site to create concrete masonry units (CMUs) for use in the development. The pop-up plant also helps the environment by eliminating truck traffic, reusing waste, and reducing the need for imported materials.

The pop-up plant applies ultra-high compression to loose excavated material, transforming the waste into a sustainable CMU. The mineral grains turn into a sort of sedimentary rock under pressure, mimicking the natural geological process of lithification. Watershed’s new technology is based on their compression technique developed earlier to reduce the amount of cement used in concrete blocks by 50 per cent.

David Easton, the founder of the sustainable building materials startup explains that the practice of building masonry structures from local materials is nothing new, with some of the oldest architecture in the world constructed from stone and clay sourced directly on site. However, thanks to upgraded technology and improved material science, a construction waste product that the developer had to previously pay to dispose of, can now become an asset and also provide environmental benefits.

Sample structural masonry block produced using excavated soil samples from the Kirkham site. Image Courtesy of Watershed Materials/Archdaily

Watershed Materials’ ground-breaking development happened in response to an enquiry from Naomi Porat, development manager of Alpha Group and part of the team working on the Kirkham Project, an urban infill redevelopment in San Francisco.

The Kirkham Project Community Plaza, a one-quarter acre accessible open space in the center of the development, provides excellent opportunities for installation of Watershed Materials blocks as pavers and landscaping features. Image Courtesy of Watershed Materials/Archdaily

The Kirkham Project, which addressed the city’s need for additional housing, consisted of 445 new housing units, community plazas and gardens. When neighbours began expressing concerns over construction traffic, the project site became the perfect place to assess the pop-up plant’s feasibility. During the study, the Kirkham Project team identified compelling advantages of the onsite process including reduced truck traffic, diesel emissions and impact on neighbours as well as significant cost savings.