Chemical treatment is one of the popular methods dealing with geoenviromental problems related to soil, such as waste dredged materials, soil with heavy metal pollutions, among others. This paper performed a series of laboratory tests to investigate the effect of phosphogypsum on water content, density, pH, unconfined compressive strength and deformation modulus of cement stabilized soil. It is found that the water content and pH value decreased whereas the density increased, as the phophogysum content increased. These changes were attributable to the formation of ettringite related to the chemical reaction between phosphogypsum and cementitious materials (calcium aluminate hydrates). The unconfined compression strengths of the cement stabilized soil with phosphogypsum content of 1.4% to 8.6% were approximately 1.7 to 9.4 times of those without phosphogypsum. Particularly, the earlier strength of the stabilized soil with phosphogypsum cured at 3 and 7 days increased by 1.3 and 2.1 times in comparison with those lacking phosphogypsum. The mineralogical changes revealed that when the cementation bonding was sufficiently formed at 28 days of curing, the increase in ettringite with phosphogypsum content behaved positive influence on strength development of cement stabilized soil. When cementation bonding was relatively low before 7 days of curing, adequate phosphogypsum content might produce moderate level of ettringite, tended to swell and make denser fabric, resulting in the strength increase. It should be also noted that over-dosage of phosphogypsum might cause volume increase and structure disruption, leading to the strength loss.

化学处理是处理与土壤有关的地球环境问题的流行方法之一，例如，疏dr的废料，重金属污染的土壤等。本文进行了一系列实验室测试，以研究磷石膏对水泥稳定土的水含量，密度，pH，无侧限抗压强度和变形模量的影响。发现随着磷糖含量的增加，水含量和pH值降低而密度增加。这些变化归因于钙矾石的形成，钙矾石与磷石膏和水泥质材料（铝酸钙水合物）之间的化学反应有关。磷石膏含量为1.4％至8.6％的水泥稳定土的无侧限抗压强度约为1.7至9。无磷石膏的4倍。特别地，与不含磷石膏的土壤相比，经磷石膏固化的稳定土壤在3天和7天的早期强度提高了1.3倍和2.1倍。矿物学变化表明，当养护28天时充分形成胶结结合时，钙矾石和磷石膏含量的增加对水泥稳定土的强度发展具有积极影响。当固化前7天的胶结结合力相对较低时，足够的磷石膏含量可能会产生适量的钙矾石，易于溶胀并使织物致密，从而导致强度提高。还应注意的是，过量施用磷石膏可能会导致体积增加和结构破坏，从而导致强度损失。与没有磷石膏的土壤相比，磷石膏固化的稳定土壤在3天和7天时的早期强度提高了1.3倍和2.1倍。矿物学变化表明，当养护28天时充分形成胶结结合时，钙矾石和磷石膏含量的增加对水泥稳定土的强度发展具有积极影响。当固化前7天的胶结结合力相对较低时，足够的磷石膏含量可能会产生适量的钙矾石，易于溶胀并使织物致密，从而导致强度提高。还应注意的是，过量施用磷石膏可能会导致体积增加和结构破坏，从而导致强度损失。与缺乏磷石膏的土壤相比，磷石膏固化的稳定土壤在3天和7天时的早期强度提高了1.3倍和2.1倍。矿物学变化表明，当养护28天时充分形成胶结结合时，钙矾石和磷石膏含量的增加对水泥稳定土的强度发展具有积极影响。当固化前7天的胶结结合力相对较低时，足够的磷石膏含量可能会产生适量的钙矾石，易于溶胀并使织物致密，从而导致强度提高。还应注意的是，过量施用磷石膏可能会导致体积增加和结构破坏，从而导致强度损失。