A recent study in Frontiers in Materials by Kaiyan Wen, Yuhua Zhan, Qiang Feng, Mengting Wei, Zhiwei Tang, Ziyao Wei, and Yulong Zhao evaluates the tri-axial shear performance of urban dredged silt stabilized using a biochar-modified alkali-activated slag binder. Urban dredged silt generally presents poor water stability, weak particle bonding, and high natural moisture contents, restricting its direct reuse in earthwork engineering and subgrade construction. To address these challenges without relying on carbon-intensive ordinary Portland cement, the researchers implemented a response surface methodology to optimize a sustainable binder formulation composed of agricultural and industrial by-products.

The experimental findings reveal that incorporating the optimized biochar-modified alkali-activated slag binder significantly enhances the mechanical properties and shear strength parameters of the treated silt. Specifically, tri-axial testing demonstrates that increasing the binder dosage from 5% to 15% improves both total-stress cohesion and internal friction angle. Water content also plays a critical role, with an 18% moisture level yielding optimal shear performance close to the compacting optimum of the mixture. Furthermore, comparative analysis indicates that the biochar-amended binder achieves a cohesion of 195.2 kilopascals and a friction angle of 42.5 degrees at 28 days, closely matching ordinary Portland cement controls while significantly surpassing traditional lime-stabilized and unamended alkali-activated slag groups. These outcomes establish a viable, clinker-free pathway for turning problematic municipal waste into robust geomaterials for infrastructure applications.

Source: Wen, K., Zhan, Y., Feng, Q., Wei, M., Tang, Z., Wei, Z., & Zhao, Y. (2026). Tri-axial shear performance of urban dredged silt stabilized with a biochar-modified alkali-activated slag binder. Frontiers in Materials, 13, 1955304.