Stabilization Mechanism of Calcium Lignosulphonate Used in Expansion Sensitive Soil
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https: //doi. org/10.1007/s11595-020-2329-y
Stabilization Mechanism of Calcium Lignosulphonate Used in Expansion Sensitive Soil WU Dajiang1, SHE Wei1*, WEI Luansu1, ZUO Wenqiang1, HU Xiangyu1, HONG Jinxiang2, MIAO Changwen1
(1. Jiangsu Key Laboratory for Construction Materials, Southeast University, Nanjing 211189, China; 2. Sobute New Materials Co. Ltd, Nanjing 211103, China)
Abstract: A series of tests were performed to investigate the macroscopic properties and the stabilization mechanism of calcium lignosulphonate modified expansive soil. Compared with natural soil, soil modified by 4% calcium lignosulphonate showed 56.5% increased 28 days unconfined compressive strength and 23.8% decreased free expansion rate. The X-ray diffraction analysis results indicate the existence of cation exchange and the reduction of montmorillonite interplanar spacing. The X-computed tomography results demonstrate that calcium lignosulphonate decreased the porosity and optimized the pore distribution. The calcium lignosulphonate also increased the stability of the suspension system according to the Zeta potential results. Moreover, the results of rheological tests show that the moderate amount of calcium lignosulphonate enhanced the yield stress and the plastic viscosity, proving the formation of a strong connection between soil particles. Key words: calcium lignosulphonate; expansive soil; mechanical characteristic; stabilization mechanism
1 Introduction Expansive soils are extensively distributed and have posed significant challenges to the civil engineering field. Due to their low strength, high plasticity, high swelling, and great shrinkage potential characteristics[1], the expansive soils require to be stabilized effectively, otherwise problems including unacceptable lateral movement, pavement cracking and road humps would appear[2-4], leading to structural deterioration of infrastructures, waste of resources, and even casualties[5,6]. In order to mitigate the expansive soils problems, quantities of techniques have been developed mainly including physical, mechanical and chemical stabilization methods [7]. In recent decades, the chemical stabilization method is more recommended due to its efficiency and replication[8,9]. Previous researches have witnessed the © Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature 2020 (Received: Apr. 29, 2019; Accepted: June 18, 2020) WU Dajiang (吴大江): Ph D; E-mail: [email protected] *Corresponding author: SHE Wei (佘伟) : Assoc. Prof.; Ph D; E-mail: [email protected] Funded by National Natural Science Foundation of China (Nos.51890904 and 51508090), National Key Technology R&D Program of China (No.2017YFB0309904), the National Basic Research Program of China (973 Program) (No.2015CB655100)
outstanding effectiveness of traditional chemical stabilizer containing lime[10,11], cement[12,13], and fly ash[14,15] on improving the unconfined compressive strength, water stability and durability of expansive soils[16-18]. However, their negative environmental im
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