丙烯酰胺聚合固化盐渍土试验研究

滨海盐渍土中易溶盐遇水溶解，引起强度明显下降，变形增大，严重影响其作为生土材料的工程性能。利用丙烯酰胺（AM）原位聚合对盐渍土进行改良，探讨固化条件对其力学性能与耐水性能的影响。试验结果表明，当加热温度为70 ℃、加热时间为6 h，AM单体用量为盐渍土用量的3%，引发剂用量为AM用量的3%，且不加入交联剂时，用量较为经济且具有较高的抗压和抗折强度，在龄期为7、14、28 d时，其抗折强度分别可达到2.265、3.603、5.255 MPa；抗压强度分别达到5.6、13.7、16.2 MPa；与28 d龄期的原试样进行对比，AM聚合固化后试样的抗折强度和抗压强度分别提高了4～5倍，相比传统砌体砂浆材料强度大幅提高，加固后试样的耐水性能和收缩率也都得到明显的改善。利用电镜扫描（SEM）、X射线衍射光谱（XRD）对其微观机制变化进行了初步探讨，发现改良后土样孔隙含量大大减小，且其矿物结构并未发生变化，可视为一种新型环保生土建筑材料应用于工程建设中。

An experimental study of acrylamide polymerized solidification of saline soil

The dissolution of a soluble salt in the inshore saline soil may cause a reduction in strength and an increase in deformation of the soil, which will seriously deteriorate the performances of immature soil material. The acrylamide (AM) polymerization technique is used to improve the saline soil, and the effects of AM and curing conditions on the mechanical properties of saline is analyzed. The results show that when the temperature rises up to 70 ℃, the drying time is 6 hours, the dosage of acrylamide monomer is 3% of saline soil mass, and initiator dosage is 3% of AM mass; furthermore, when the crosslinking agent is not added, the improved saline soil has higher compressive and flexural strengths of the improved saline soil, while the dosages of the various agents are economical; the flexural strength of the soil can reach 2.265, 3.603, 5.255 MPa, and the compressive strength is 5.6, 13.7, 16.2 MPa when the curing age is 7, 14 and 28 d, respectively. Compared with plain saline soil adobe, the compressive and flexural strengths (28 d) of modification saline soil adobe increase 4-5 times respectively, much higher than those of the traditional masonry mortar. At the same time, water resistance and shrinkage are improved significantly. The microscopic mechanism of strength improvement is analyzed using the scanning electron microscope (SEM) and X-ray diffraction spectrum (XRD), it is found that the porosity decreases significantly but mineral structure of solidified soil remains unchanged. AM polymerized solidification of saline soil can be considered as a kind of new environment friendly building materials used in construction projects.