Physicochemical and index properties of loess stabilized with lime and fly ash piles

• The physicochemical and index properties in loess stabilized with lime and fly ash piles were examined.
• Ion migration induces hydration and pozzolanic reactions in loess surrounding the piles.
• These reactions alter loess properties due to the interparticle flocculation and aggregate formation.

This study examines physicochemical and index properties of loess modified by adding lime and fly ash piles. After curing for 28 days, modified loess samples were obtained at various radial distances from the lime and fly ash piles (i.e., 5 cm, 10 cm 15 cm, and 20 cm). Various index properties were then measured: water content, density, Atterberg limits, and Equotip hardness value. The physicochemical properties were also measured, including specific surface area (SSA), cation exchange capacity (CEC), X-ray diffraction (XRD), and disintegration rate. The test results showed increases in SSA, CEC, water content, and liquid limit at distances from 5 cm to 20 cm, whereas density and the plastic limit decreased with radial distance. Moreover, the hardness value show an inverse relation with increasing radius for loess with lime and fly ash piles. The data obtained from XRD analysis and slake tests confirm that lime and fly ash migrate into loess surrounding the pile and consequently cause changes in physicochemical and index properties. These changes can be explained by the interaction between the structure and mineral composition. This interaction forms new cementitious products are formed by the hydration and pozzolanic reaction due to cation exchange, and consequently the interparticle flocculation and aggregate formation. These results indicate that lime and fly ash piles can be used as a convenient and efficient stabilization method to improve the performance of collapsing loess.