Evaluating sulfur-free lignin as a sustainable additive for soil improvement against frost resistance

Liu, Yaowu; Zheng, Wenle; Wang, Qing; Cao, Chengjun; Chang, Mushi; Rocchi, Irene

doi:10.1016/j.jclepro.2019.119504

Cited by 33 publications

(9 citation statements)

References 63 publications

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“…This result indicated that CLPs differed from calcium-based stabilizers and did not produce new compounds that affected soil crystallization. These findings are consistent with those of Liu et al (2020) and Zhang et al (2016). CLPs contain hydrophilic functional groups, such as -OH, -COOH, and -NH 2 , leading to changes in the functional groups of treated loess.…”

Section: Stabilization Mechanism Of Solidified Loesssupporting

confidence: 89%

A Cross-Linked Polymer Soil Stabilizer for Hillslope Conservation on the Loess Plateau

et al. 2021

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The soil of the Loess Plateau is highly susceptible to erosion due to its distinct loess structure with poor water stability and disintegrates easily. Previous research has focused on improving soil strength without considering stability and ecological performance. Comprehensive improvements may be achieved by cross-linked polymers (CLPs), but their effect on loess structure remains unclear. In the present study, we investigate CLPs as a new organic soil stabilizer to improve soil aggregate stability. To determine the effect of CLPs on the stabilization of loess, a series of indoor tests was conducted to assess unconfined compressive strength, water stability, soil-water characteristics, and plant height. The stabilization mechanism was analyzed by comparing the microstructure, mineral composition, and features of functional groups of loess before and after treatment. The results showed that, compared with untreated loess, the unconfined compressive strength and anti-disintegration property of treated loess were significantly increased. The water retention capacity was improved, and the germination rate and growth of plants were promoted. Microscopic analysis showed that the use of CLPs did form new minerals in the loess or change the functional groups, rather, CLPs improved the microstructure, reduced the total volume of pores, and increased the degree of soil compaction. Field tests showed that the erosion of loess hillsides was effectively controlled by CLPs. Under the same erosive conditions, the slope surface treated with CLPs was more intact than the untreated slope surface. Our findings provide new strategies regarding the application of CLPs as soil stabilizers to control loess erosion and promote vegetation restoration.

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Section: Stabilization Mechanism Of Solidified Loesssupporting

confidence: 89%

A Cross-Linked Polymer Soil Stabilizer for Hillslope Conservation on the Loess Plateau

et al. 2021

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“…As shown in Figure 8, lignin fills the micropores formed by fine-grained particles indicating that the possible mechanism responsible for hydraulic conductivity reduction consists mainly of physical binding [62]. A similar mechanism has been recently proposed by reference [30], indicating that the stabilization mechanism differs from traditional soil stabilizers (i.e., lime). Some attempt was made to investigate the mechanism responsible for the reduction in soil permeability.…”

Section: Effect Of Lignin On Hydraulic Conductivity Of Soil Sasupporting

confidence: 70%

“…As reported by reference [28], SFL could yield comparable strength to fly ash treatment. Moreover, the soil stabilized with SFL may provide excellent moisture and frost resistance [24,29,30].…”

Section: Introductionmentioning

confidence: 99%

Perspectives of Using Lignin as Additive to Improve the Permeability of In-Situ Soils for Barrier Materials in Landfills

et al. 2020

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Very often, in-situ soil does not meet the requirements for landfill barriers; therefore, it is necessary to purchase the material from quarries. An increasing number of by-products have been proposed as alternative landfill barrier materials. The present study investigated the performance of two soils of Central Italy (alluvial and volcanic soils) with an organosolv lignin (sulfur-free lignin (SFL)), a widespread by-product in the world. Laboratory investigations indicated that the volcanic soil mixed with 10% in weight of lignin did not reach the permeability value required for landfill bottom liners, also showing high compressibility. On the contrary, the addition of 20% to 30% lignin to the alluvial soil reached the permeability value recommended for the top-sealing layer of landfills: scanning electron microscope analysis indicated that the improvement was due mainly to the physical binding. Large-scale investigations should be carried out to evaluate the long-term performance of the mixtures. The increasing production of organosolv lignin worldwide gives this by-product the opportunity to be used as an additive for the realization of the top-sealing layer. The approach can save the consumption of raw materials (clayey soils from quarries), giving lignin a potential new field of application and recovering in-situ soils.

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“…The optimal UCS values of several modified soils are listed in Figure 6 e [ 35 , 36 , 37 , 38 , 39 , 40 ], where the UCS of PVDF-MCM in our work is very prominent. On the other hand, the TS values of many modified soils does not exceed 0.5 MPa under the corresponding optimal conditions [ 32 , 41 , 42 , 43 , 44 , 45 ]; However, in our work, the TS of PVDF-MCM can reach ~2 MPa ( Figure 6 f) [ 46 ].…”

Section: Resultsmentioning

confidence: 97%

Hydrophobic Polymeric Additives toward a Long-Term Robust Carbonaceous Mudstone Slope

Chen

Zha

et al. 2021

Polymers

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Slopes with carbonaceous mudstone (CM) are widely distributed in the southwest of China and have experienced numerous geological disasters in special climate, especially in rainfall conditions. Therefore, novel materials to stabilize CM slopes have attracted increasing interests. However, developing ultra-stable and cost-effective additives for CM slopes is still a great challenge. Herein, a hydrophobic polymeric material (polyvinylidene fluoride, PVDF) is investigated as an additive to enhance the mechanical strength and long-time stability of CM slopes. The PVDF is uniformly dispersed in CM matrix via interfacial interaction. The contact angle of the PVDF-modified carbonaceous mudstone (PVDF-MCM) can reach as high as 103.95°, indicating an excellent hydrophobicity. The unconfined compressive strength (UCS) and tensile strength (TS) of PVDF-MCM have been intensively enhanced to 4.07 MPa and 1.96 MPa, respectively, compared with ~0 MPa of pristine CM. Moreover, the UCS and TS of PVDF-MCM remain at 3.24 MPa and 1.03 MPa even after curing for 28 days in high humidity conditions. Our findings show that the PVDF can improve the hydrophobicity of CM significantly, which leads to super mechanical stability of PVDF-MCM. The excellent performance makes PVDF a promising additive for the development of ultra-stable, long-lifetime and cost-effective carbonaceous mudstone slopes.

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Evaluating sulfur-free lignin as a sustainable additive for soil improvement against frost resistance

Cited by 33 publications

References 63 publications

A Cross-Linked Polymer Soil Stabilizer for Hillslope Conservation on the Loess Plateau

A Cross-Linked Polymer Soil Stabilizer for Hillslope Conservation on the Loess Plateau

Perspectives of Using Lignin as Additive to Improve the Permeability of In-Situ Soils for Barrier Materials in Landfills

Hydrophobic Polymeric Additives toward a Long-Term Robust Carbonaceous Mudstone Slope

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