Vishweshwaran Muralidaran, Sujatha Evangelin Ramani, Baldovino Jair Arrieta
Centre for Advanced Research in Environment, School of Civil Engineering, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
Applied Geotechnical Research Group, Department of Civil Engineering, Universidad de Cartagena, Cartagena de Indias 130015, Colombia.
Polymers (Basel). 2024 Jun 3;16(11):1586. doi: 10.3390/polym16111586.
The freeze-drying of biopolymers presents a fresh option with greater potential for application in soil subgrade stabilization. A freeze-dried combination of β-glucan (BG) and γ-poly-glutamic acid (GPA) biopolymers was used to treat low compressible clay (CL) and low compressible silt (ML) soils in dosages of 0.5%, 1%, 1.5%, and 2%. The California bearing ratio (CBR) test for the treated specimens was performed under three curing conditions: (i) thermal curing at 60 °C, (ii) air-curing for seven days followed by submergence for 4 days, and (iii) no curing, i.e., tested immediately after mixing. To investigate the influence of shear strength on the freeze-dried biopolymer-stabilized soil specimens and their variations with aging, unconfined compressive strength (UCS) tests were conducted after thermal curing at 60 °C for 3 days, 7 days, and 7 days of thermal curing followed by 21 days of air curing. The maximum CBR of 125.3% was observed for thermally cured CL and a minimum CBR of 6.1% was observed under soaked curing conditions for ML soils. Scanning electron microscopy (SEM), infrared spectroscopy, average particle size, permeability, and adsorption tests revealed the pore filling, biopolymer adsorption and coating on the soil surface, and agglomeration of the soil along with the presence of hydrogen bonds, covalent amide bonds, and Van der Waals forces that contributed to the stiffening of the stabilized soil. Using three-dimensional (3D) finite element analysis (FEA) and layered elastic analysis (LEA), a mechanistic-empirical pavement design was carried out for the stabilized soil and a design thickness catalog was prepared for the maximum CBR. The cost reductions for a 1 km section of the pavement were expected to be 12.5%.
生物聚合物的冷冻干燥为土壤路基稳定化提供了一种全新且具有更大应用潜力的选择。使用β-葡聚糖（BG）和γ-聚谷氨酸（GPA）生物聚合物的冷冻干燥组合，以0.5%、1%、1.5%和2%的剂量处理低压缩性黏土（CL）和低压缩性粉土（ML）。对处理后的试样进行加州承载比（CBR）试验，试验在三种养护条件下进行：（i）60℃热养护；（ii）空气养护7天，随后浸泡4天；（iii）不养护，即混合后立即测试。为了研究抗剪强度对冷冻干燥生物聚合物稳定土试样的影响及其随龄期的变化，在60℃热养护3天、7天以及热养护7天后再空气养护21天后进行无侧限抗压强度（UCS）试验。热养护的CL试样的最大CBR为125.3%，而ML土在浸泡养护条件下的最小CBR为6.1%。扫描电子显微镜（SEM）、红外光谱、平均粒径、渗透性和吸附试验揭示了孔隙填充、生物聚合物在土壤表面的吸附和包覆以及土壤的团聚，同时存在氢键、共价酰胺键和范德华力，这些因素导致了稳定土的硬化。使用三维（3D）有限元分析（FEA）和层状弹性分析（LEA），对稳定土进行了机理-经验路面设计，并针对最大CBR编制了设计厚度目录。预计1公里长的路面路段成本降低12.5%。
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