Experimental Study on the Physical and Mechanical Properties of Loess Improved by an LM-1 Curing Agent and Cement Composite

This study focuses on loess in the Lanzhou region and employs a self-developed LM-1 ionic cementitious curing agent (mainly sodium silicate) combined with cement for loess improvement. Through mechanical tests, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) analysis, the mechanical properties, microstructure, and mineralogical evolution of composite-improved loess were systematically investigated, with emphasis on revealing the reinforcement mechanism. The results show that combining LM-1 and cement significantly enhances the unconfined compressive strength (UCS) of loess. The optimal proportion of 1.5% LM-1 + 10% cement achieves 7-day and 28-day UCS values of 3.43 MPa and 4.12 MPa, representing increases of 69.0% and 54.7% over 10% cement alone, and outperforming 12% cement-only specimens. This formulation develops a uniform, dense C-S-H gel network with optimized pore structure and reduced microcracks. LM-1 generates hydrated silicate products through alkali-activated reactions, which together with cement hydration C-S-H gel form a dual-gel cementation system, while effectively accelerating cement hydration. This provides a theoretical basis and technical support for balancing cement reduction and performance enhancement in subgrade reinforcement and slope protection in loess regions.