Structural Stability and Mechanical Behavior Improvement of Loess Soil Treated with Marble Waste–Cement Hybrid

Abstract

The stabilization of unstable Loess soil and the mitigation of industrial waste environmental impacts are achieved through a hybrid system integrating Waste Marble Dust (WMD) as a sustainable additive and 3% Portland cement as a hydraulic binder. Experimental investigations identified the 20% WMD blend as the optimal threshold for peak geotechnical stability; the Maximum Dry Density (γd) surged from 14.2 to 19.5 kN/m³, and the California Bearing Ratio (CBR) exhibited a structural surge from 5.14% to 97.16%. Cohesion (Crose significantly from 11 to 152 kPa, while the Unconfined Compressive Strength (UCS) peaked at 279 kPa after 56 days of curing. Hydraulically, the permeability coefficient (k) significantly declined from 7.04 ×  m/s in the natural state to 1.06 ×  m/s in the stabilized matrix, reflecting superior microscopic densification and seepage resistance.

At the mineralogical level, X-ray diffraction (XRD) analysis confirmed a fundamental phase transformation characterized by the consumption of unstable clay phases and the synthesis of calcium silicate and aluminate hydrates (C-S-H and C-A-H). The findings validate that the functional synergy between cementitious pozzolanic reactions and the WMD filler effect established a compact crystalline framework. Consequently, this hybrid approach transforms weak soil into a sustainable geotechnical composite with high structural integrity and durability, effectively fulfilling industrial waste recycling goals in infrastructure development