Abstract: Under the vision of global sustainable development, the abandoned sandy soil produced in the process of water conservancy construction needs to be improved because of its loose structure, low compressibility and high permeability, so as to promote the construction of ecological civilization and the sustainable utilization of land resources. High-performance curing agent was prepared by solid waste-based sulfur-aluminum-iron cementitious materials, gypsum and granulated high-alumina slag, and the effects of additives such as glass fiber powder, carbon nanotubes, resin rubber powder and oil sludge residue were explored. The results showed that after adding cementitious materials and additives, the maximum unit volume mass of solidified soil increased, and the strength of solidified soil increased to 10.7 to 18.1 times that of natural sandy soil, which met the strength requirements of secondary highway subbase. In addition, the impermeability of solidified soil had excellent performance, especially the combination of oil sludge residue and cementitious materials, and its 7 d permeability coefficient was reduced by 25% compared with that of simple cementitious materials solidified soil. XRD and SEM analysis revealed that ettringite and hydrated calcium silicate gel were the main filling and cementing components. Admixtures could improve the properties of solidified soil through mechanisms such as accelerated hydration of carbon nanotubes, reinforcement of glass fiber powder, bonding of resin powder and filling and bonding of oil sludge residue. This study not only provides a method for the efficient utilization of sand in the construction field, but also opens up a new way for the resource utilization of solid waste such as pyrolysis residue of oil sludge.

Key words: sandy soil solidification, admixtures, sulfur-aluminum-iron low-carbon cementitious materials, recycling of resources