Author(s)

Shuang Huang, Dazhi Guan, Wucheng Tian, Guang Yang

Corresponding Author

Shuang Huang

Abstract

Given its substantial role as industrial solid waste, the use of fly ash as a resource is vital for reducing environmental pollution. In this study, five types of anti-seepage additives were selected for mixing with fly ash, namely NaCl, sodium bentonite, CaCl2, CaO, and fiber. To prepare the desired samples and evaluate their permeability characteristics, the materials were uniformly mixed with conventional hydraulic ash at varying ratios. Using the ideal material, the blending and mixing ratios exhibiting the lowest hydraulic conductivity (K) were identified. In addition, variations in the hydraulic conductivity of an optimal anti-seepage material influenced by frost heave and acid-base scenarios were evaluated in cold regions. It was found that NaCl and sodium bentonite exhibited the lowest hydraulic conductivities among all blended substances. The ideal ratio of fly ash to NaCl was determined to be 35:1, whereas that of fly ash to sodium bentonite was 10:1. As the number of frost heave cycles increased, a minor increase was observed in the hydraulic conductivities of both substances; however, this upward trend slowly diminished. Following immersion for 30 d in potent acid and alkali solutions, the hydraulic conductivities of both substances increased compared to their pre-soaked states. Solutions containing acids exhibited a more pronounced corrosive effect on the substances than those with alkaline properties. Nonetheless, under frost heave and acid-base conditions, the hydraulic conductivities of both substances remained <1×10−5 m/d, thereby fulfilling the fundamental criteria for anti-seepage materials.

Keywords

Fly ash, hydraulic conductivity, impervious material, optimal mixing ratio