Analysis on compression characteristics and microscopic structure of heterogeneously stabilized lumpy soils

To explore the influence of inadequate cutting and mixing on the replacement engineering, the lumpy wastes of different sizes were prepared to investigate the compression behavior of the heterogeneously stabilized lumpy waste. The influence and mechanism of phosphogypsum ratio on the performance of heterogeneously stabilized lumpy soils were explored, in order to realize the utilization of phosphogypsum solid waste and reduce the energy consumption of solidifying agents. The results show that the compressibility of the ce-ment-phosphogypsum synergistic heterogeneously stabilized lumpy waste is significantly reduced, and the pre-yielding stress first increases to 392 kPa and then decreases as the lump diameter increases to 7 mm. The stabilization quality gradually reaches the optimum and then decreases as the content of phosphogypsum increases, and the optimal mass fraction of phosphogypsum at the age of 28 d is 30% of the cement. The hydration products of the binder form a stiff-shell crust on the surface of the lumps, forming a force-bearing skeleton. The ettringite formed by the hydration reaction of phosphogypsum and cement's hydration products has remarkable expansibility, and partially fills the pores among lumpy wastes, thus reducing the compressibility. The excessive phosphogypsum will lead to internal stress of the stiff-shell layer, resulting in the reduction of preyielding stress. © 2024 Southeast University. All rights reserved.