Researchers in China have shown that a mix of fly ash and blast furnace slag, activated with alkalis, can turn dredged mud into a strong embankment filler. The treated soil beat cement-treated fill on compressive strength, tensile strength, and water stability when used at a 10% binder dose. A life cycle assessment found the new binder cuts global warming potential by about 99% compared with conventional cement treatment, while also reducing acidification, eutrophication, and resource use. Unlike Portland cement, which is responsible for a large share of industrial CO2 emissions, the new binder is made almost entirely from industrial by-products that would otherwise be landfilled. The study used dredged silt from Nanjing and tested a range of formulations to find the best mix. The authors say future work should test the material against sulfate attack, high temperatures, and freeze-thaw cycles before it is used in real embankments.
