Bian Xiaoya, Xia Junjian, Liu Hui, Xiao Tianyu
School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430074, China.
Materials (Basel). 2025 Apr 25;18(9):1960. doi: 10.3390/ma18091960.
The accumulation of silty soils and industrial solid waste not only results in a significant waste of land resources but also causes environmental pollution. Phosphogypsum and cement are commonly utilized as binding agents for the solidification of silt in engineering applications. However, the use of PG and cement alone may lead to issues such as insufficient strength, crack formation, and poor durability. Therefore, this research considered and employed a two-phase stabilization method using phosphogypsum and cement to solidify silt. Additionally, to further enhance the durability of the stabilized silt, polypropylene fiber (PP) and sodium sulfate (NaSO, NS) were incorporated. The effects of two-phase phosphogypsum and the proportion of hemihydrate phosphogypsum (BHPG) in the two-phase phosphogypsum on the strength characteristics of the stabilized silt were investigated through unconfined compressive strength tests and durability tests. The results show that when the content of two-phase phosphogypsum is 5%, and the proportion of BHPG in the two-phase phosphogypsum is 20%, the 28-day unconfined compressive strength of the stabilized silt reaches 1.42 MPa, and the deformation modulus is 95.5 MPa. After incorporating sodium sulfate (NS), the water and frost resistance of the stabilized silt significantly improved. The microstructural analysis shows that NS promotes the formation of ettringite. Furthermore, an excessively high proportion of hemihydrate phosphogypsum (BHPG) in the two-phase phosphogypsum content can lead to dihydrate phosphogypsum (2HPG) not being encapsulated by hydration products, which results in a less dense structure of the solidified silt and a decline in performance.
粉质土和工业固体废弃物的堆积不仅造成土地资源的大量浪费，还会导致环境污染。磷石膏和水泥在工程应用中通常用作粉质土固化的粘结剂。然而，单独使用磷石膏和水泥可能会导致强度不足、裂缝形成和耐久性差等问题。因此，本研究考虑并采用了一种使用磷石膏和水泥的两相稳定化方法来固化粉质土。此外，为了进一步提高固化粉质土的耐久性，还加入了聚丙烯纤维（PP）和硫酸钠（NaSO，NS）。通过无侧限抗压强度试验和耐久性试验，研究了两相磷石膏以及两相磷石膏中半水磷石膏（BHPG）的比例对固化粉质土强度特性的影响。结果表明，当两相磷石膏含量为5%，且两相磷石膏中BHPG的比例为20%时，固化粉质土的28天无侧限抗压强度达到1.42MPa，变形模量为95.5MPa。加入硫酸钠（NS）后，固化粉质土的抗水抗冻性显著提高。微观结构分析表明，NS促进了钙矾石的形成。此外，两相磷石膏中半水磷石膏（BHPG）比例过高会导致二水磷石膏（2HPG）未被水化产物包裹，从而使固化粉质土结构疏松，性能下降。
