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.

To address the issues of inadequate construction process adaptability and the lack of a rapid on-site evaluation system for loess improved by the LM-1 cement-based curing agent in practical engineering, this study systematically carried out material mix proportion design, construction process detailing, compaction degree testing, unconfined compressive strength (UCS) tests of the stabilized mixture, and in-situ light dynamic penetration tests (DPTs) based on a loess road test section in the Dingyuan area. The results show that the mix proportion of 1.5% LM-1 + 10% cement + 88.5% raw loess meets the 7-day UCS design requirement, with a water stability coefficient of 92.9%, indicating excellent water stability, and an average compaction degree of 96.6%. After 7 days of curing, the penetration blow count exceeded 130, indicating that the stabilized loess base layer possesses high penetration resistance and is generally in a dense state. The research findings fill the technical gap in the field application of the LM-1 cement-based curing agent in loess engineering, establish referable construction quality control thresholds and acceptance criteria, and provide theoretical basis and technical support for subgrade slope reinforcement in loess regions.