Biopolymer Based Soil Treatment for Geotechnical Engineering Applications

Sujatha, Evangelin Ramani; O’Kelly, Brendan C.

doi:10.1007/978-981-16-6603-2_22-1

Cited by 4 publications

(3 citation statements)

References 69 publications

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“…For instance, mulch addition has been found to be effective in reducing soil losses; straw mulch is easy to apply, contributes soil OM, and is efficient from the day of application [8]. Other environmentally benign approaches and soil additives have yielded some promising results in engineering an improvement in the erosion resistance of treated coarse-grained soils, including, for instance, using bio-cementation via microbial-induced carbonate precipitation (MICP) [9][10][11] or various biopolymer additives [12][13][14]. The focus of the present paper is on the development of cyanobacteria-induced bio-crusts (BCs).…”

Section: Introductionmentioning

confidence: 99%

Reducing the Erodibility of Sandy Soils Engineered by Cyanobacteria Inoculation: A Laboratory Investigation

2023

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Windblown and water-induced erosion cause substantial soil losses worldwide, especially for drylands. Any sustainable management program that increases soil organic matter and improves the stability of the crustal layer could considerably enhance soil productivity and the preservation of erosion-prone land. This paper presents a laboratory investigation of cyanobacteria-inoculated medium sand and fine sand soils studied for severe runoff conditions that were simulated using an erosion function apparatus (EFA). Loosely deposited sand specimens prepared by air-pluviation were inoculated with a single native filamentous-cyanobacterium strain (investigating both Nostoc sp. and Calothrix sp.) and then incubated under high exposure to white light for 32- or 48-day periods. Well-developed bio-crusts were produced on the specimens’ top surface that achieved substantial improvements in erosion resistance, as was demonstrated for a wide range of hydraulic shear stress investigated using EFA experiments. Relative improvements in hydraulic erosion resistance were explained in terms of the nature of the cyanobacteria-developed microstructures (cyanobacteria filament infiltration of pore-void spaces and exopolysaccharide excretion), as were observed by scanning electron microscope examinations. The developed microstructure depended on the cyanobacterium strain employed and the nominal pore-void sizes that are related to the sand gradation and density state. The encouraging findings of this experimental investigation suggest a tailored approach (i.e., employing a suitable native cyanobacterium strain chosen for its compatibility with the soil’s physical properties) could lay the basis for developing a novel technology for soil protection.

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Section: Introductionmentioning

confidence: 99%

Reducing the Erodibility of Sandy Soils Engineered by Cyanobacteria Inoculation: A Laboratory Investigation

2023

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“…The geotechnical engineering sector uses huge quantities of chemical additives (traditionally lime and cement), as binders, in many soil stabilization and ground improvement applications. Chemical additives lastingly change the treated soil environment and can cause pollution of groundwater [1]. Biological methods represent promising sustainable and green alternatives, and are broadly classified as (i) methods producing mineral precipitation in the soil pore voids (e.g., bio-grouting); (ii) methods transforming clay minerals from one form to another (i.e., mineral transformation); and (iii) biopolymer-based soil treatment (BBST) [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Chemical additives lastingly change the treated soil environment and can cause pollution of groundwater [1]. Biological methods represent promising sustainable and green alternatives, and are broadly classified as (i) methods producing mineral precipitation in the soil pore voids (e.g., bio-grouting); (ii) methods transforming clay minerals from one form to another (i.e., mineral transformation); and (iii) biopolymer-based soil treatment (BBST) [1,2]. To date, bio-grouting technologies in ground improvement applications have mainly employed the microbial-induced calcite precipitation (MICP) process.…”

Section: Introductionmentioning

confidence: 99%

Enzymatic-Induced Calcite Precipitation (EICP) Method for Improving Hydraulic Erosion Resistance of Surface Sand Layer: A Laboratory Investigation

et al. 2023

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As a bio-inspired calcite precipitation method, bio-grouting via enzymatic-induced calcite precipitation (EICP) uses free urease enzyme to catalyze the urea hydrolysis reaction. This soil stabilization approach is relatively new and insufficiently investigated, especially for applications involving surface layer stabilization of sandy soil deposits for increasing hydraulic erosion resistance. This paper presents a laboratory investigation on the surface erosion resistance improvements for compacted medium-gradation quartz sand specimens mediated using 10 different EICP treatment protocols. They involved single- and two-cycle injections of the urease enzyme (activity of 2400 U/L) and 0.5, 0.75, or 1.0-M urea–CaCl2 cementation solution reagents. The urease enzyme was extracted from watermelon seeds. Erosion rates were determined for various hydraulic shear stresses applied using the erosion function apparatus. The spatial distribution and morphology of precipitated calcite within the pore-void spaces of the crustal sand layer were investigated with a scanning electron microscope. Compared to untreated sand, all 10 investigated EICP treatment protocols produced substantially improved erosion resistance, especially for the higher cementation solution concentration (1.0 M). Of these 10 EICP protocols, a single cycle of enzyme–1.0-M-cementation solutions injections was identified as the more pragmatic option for achieving near-optimum erosion resistance improvements. Highest and lowest amounts (18.8 and 5.0 wt%) of precipitated calcite corresponded to the best and worst performing EICP-treated specimens, although the calcite’s spatial distribution in treated specimens is another important factor.

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