Evaporation and cracked soda soil improved by fly ash from recycled materials

Abstract The osmotic pressure of a soil solution increases due to soil salinization and the stability and sustainability of the soil becomes poor, which will affect the movement of water in soil. In this study, the evaporation capacity and desiccation cracking characteristics of soda soil samples with different content (5, 10, 15, 20, and 25% by weight) of fly ash were investigated. After drying, the unconsumed water content of soil increased from 8.55 to 16.22%. The results indicate that the water retention capability of soda soil can be improved by the addition of the fly ash. The addition of fly ash is beneficial to the formation of soil aggregates and pores in the fly ash can store water. The fractal dimension and crack growth rate can be used to quantitatively describe the crack characteristics of a sample. The maximum fractal dimension of the soil samples decreased by 2.05, 3.92, 11.89, 8.53, and 3.07%, respectively, and the crack intensity factor (CIF) decreased by 4.65, 14.13, 22.48, 10.05, and 15.87%, respectively, with an increase of fly ash. Fly ash can therefore effectively inhibit crack growth and reduce the crack length in soda soil, since the clay content of soda soil decreased owing to the addition of fly ash, and the tensile properties were improved owing to the pore structure of fly ash. The shrinkage and evaporation of soil are closely related to soil quality factors such as clay content, mineral composition, and structure.