关键词: 丙烯酰胺, 原位聚合, 力学性能, 盐渍土, 微观机制

Abstract: 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.

Key words: acrylamide (AM), in-situ polymerization, mechanical properties, saline soil, microscopic mechanism