Popularized in the 1990s, liquefied soil stabilisation is one tactic to reuse excavated soil and toxic sludge at construction sites.

The construction-generated waste is mixed with cement or other coagulating materials and reused as backfill for support and ground stabilization.

A team of researchers at Shibaura Institute of Technology (SIT) has recently shown that modifying the solidifiers and thickeners can help avoid the existing structural and environmental limitations of liquefied stabilised soil.

"Construction sludge and excavated soil has traditionally been considered waste, but its disposal bears an environmental cost. We are pursuing creative ways to regenerate this waste so it can serve as an environmentally friendly resource,” said Prof. Inazumi.

To overcome environmental and structural limitations, the team used a cellulose-based thickener to prevent the bleeding phenomenon and maintain fluidity.

Moreover, ordinary Portland cement (OPC) solidifier was substituted with a mixture of earth silica-blast furnace slag powder (ES-B).

ES-B is more sustainable as it does not contain any chromium, its components can be changed to adjust the rate of curing, and when mixed with soil, it allows homogenous mixing and better fluidity of the end product.

The reuse of waste material will also progress the circularity of construction projects, resulting in cost savings and reduced environmental impact.