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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。
The soluble salt in coastal saline soil dissolves with water, causing the strength to drop obviously and the deformation to increase, seriously affecting its engineering performance as a raw earth material. The in situ polymerization of acrylamide (AM) was used to improve the saline soils. The effects of curing conditions on the mechanical properties and water resistance were also discussed. The results show that when the heating temperature is 70 ℃, the heating time is 6 h, the amount of AM monomer is 3% of the amount of saline soil, the amount of initiator is 3% of the amount of AM, and the dosage is not more Economical and has high compressive strength and flexural strength. The flexural strength of the composites can reach 2.265, 3.603 and 5.255 MPa respectively at the ages of 7, 14 and 28 d, and the compressive strengths reach 5.6, 13.7 and 16.2 MPa Compared with the original samples aged 28 d, the flexural strength and compressive strength of AM specimens increased by 4 ~ 5 times respectively. Compared with the traditional masonry mortar, the strength of specimens increased significantly, The water resistance and shrinkage have also been significantly improved. SEM and XRD were used to investigate the microscopic mechanism. The results showed that the pore size of the improved soil sample was greatly reduced and its mineral structure did not change, which could be regarded as a new type Green building materials used in construction projects.