Investigation of the effectiveness and mechanisms of enzyme products for subgrade stabilization

Velasquez, Raul; Marasteanu, Mihai; Hozalski, Raymond M.

doi:10.1080/10298430600574395

Cited by 37 publications

(25 citation statements)

References 3 publications

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“…For this type of product, typical dosages comprise between 0.002 and 0.1 %. However, according to Tingle and Santoni (2003) and Velasquez et al (2006), the geotechnical properties of soils treated with an enzymatic additive were independent of the application rate. Therefore, a dosage of 0.002 % was selected.…”

Section: Non-traditional Additivesmentioning

confidence: 94%

“…Additionally, additives have been tested to stabilise erodible soils (Velasquez et al 2006). Mechanical properties, such as unconfined compressive strength (Santoni et al 2002;Tingle and Santoni 2003) or swelling potential of plastic soils (Katz et al 2001;Rajendran and Lytton 1997) have also been studied.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Acids are low-pH aqueous solutions containing sulfonated molecules such as naphthalene or limonene (Katz et al 2001). For enzymatic solutions, the presence of proteins was confirmed by Velasquez et al (2006). Lignosulfonates are organic polymers derived from lignin extracted by the sulphite processing of cellulose in the wood pulp and paper industries.…”

Section: Literature Reviewmentioning

confidence: 99%

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Life cycle assessment of non-traditional treatments for the valorisation of dry soils in earthworks

Blanck

Cuisinier

Masrouri

2016

Int J Life Cycle Assess

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Purpose Sustainable development principles are leading earthwork companies to use all-natural materials extracted from the construction site to build the infrastructure. Natural materials with low characteristics must be improved. For dry soils, the common solution is to increase the compaction energy or add important quantities of water to reach the target dry density and bearing capacity. To reduce the environmental impact of their activities, the use of industrial organic products has been proposed. The aim of this study was to assess the potential benefits that could be expected from the use of these non-traditional treatments in earthworks with a wellrecognised environmental impact assessment methodology. Methods Three non-traditional products were selected as follows: an acid solution (AS), an enzymatic solution (ES) and a calcium lignosulfonate (LS). For each of these categories, geotechnical properties such as compaction, bearing capacity, unconfined compressive strength and stiffness were first determined. Based on these results, the construction strategy for which non-traditional additives lead to greater improvement of soil properties was defined. The environmental balance of each option was then determined via a comparative process life cycle assessment study that considered ten impact categories. Results and discussion An experimental study showed the ability of enzymatic and lignosulfonate additives to improve soil characteristics with significant savings of water at the construction stage. The purpose of the study was also to compare the global environmental impact of each treatment strategy defined from laboratory investigations. The life cycle assessment results showed that some construction strategies lead to a significant reduction in the environmental impact compared with the reference strategy. However, these environmental improvements are strongly linked to the choice of the construction strategy and site conditions as discussed in the sensitivity analysis. Conclusions Within the three tested non-traditional additives, enzymatic and lignosulfonate treatments showed an association of technical and environmental interest for the compaction of dry soils. As demonstrated in the sensitivity analysis, these benefits are achieved when the production and transport steps have limited environmental impact. Thus, despite an important transportation distance for enzymatic additive, the small quantities that must be used (0.002 % by dry weight) have a limited contribution on the global environmental impact. In contrast, the production step strongly impacts the treatment with lignosulfonates. Moreover, environmental interest remains strongly dependent on the site conditions and construction strategy, which is why the adopted methodology can accurately perform an initial evaluation before implementing a soil treatment with a non-traditional product.

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Section: Non-traditional Additivesmentioning

confidence: 94%

Section: Literature Reviewmentioning

confidence: 99%

Section: Literature Reviewmentioning

confidence: 99%

See 1 more Smart Citation

Life cycle assessment of non-traditional treatments for the valorisation of dry soils in earthworks

Blanck

Cuisinier

Masrouri

2016

Int J Life Cycle Assess

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“…cement and lime, are adopted to modify and improve strength and durability properties of road foundation materials; however, only a few studies have been conducted where liquid enzymes were used to stabilise the properties of subgrade and unbound granular materials used in road pavement foundation. Velasquez et al (2006) concluded that the enzyme adopted in their study improved the chemical bonding that helps to fuse the soil particles together, creating a permanent structure that is more resistant to weathering, wear and water penetration. Velasquez et al (2006) also observed that the type of soil, per cent of fines and chemical composition are properties that affect the stabilisation mechanism.…”

Section: Introductionmentioning

confidence: 97%

“…Velasquez et al (2006) concluded that the enzyme adopted in their study improved the chemical bonding that helps to fuse the soil particles together, creating a permanent structure that is more resistant to weathering, wear and water penetration. Velasquez et al (2006) also observed that the type of soil, per cent of fines and chemical composition are properties that affect the stabilisation mechanism. In addition, Wright-Fox et al (1993) reported that enzymes may increase soil shear strength and that soil stabilised with enzymes should be considered but only on a case-by-case basis.…”

Section: Introductionmentioning

confidence: 97%

Quantification of the properties of enzyme treated and untreated incinerator bottom ash waste used as road foundation

Ahmed

Khalid

2011

International Journal of Pavement Engineering

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A substantial amount of incinerator bottom ash (IBA) waste is generated annually from burning municipal solid waste. IBA is similar to aggregate consisting of ferric metals, non-ferrous metals, brick and tile fragments, ceramic, glass, stone, dirt, etc. In this work, IBA waste was mixed with conventional limestone aggregate in an attempt to achieve a blend with acceptable mechanical properties and minimum environmental risks for use in road foundation layers. Enzyme treatment was applied in order to improve the behaviour of IBA-limestone blends. A series of laboratory tests, such as cyclic triaxial compression tests, pH monitoring and scanning electron microscope, were adopted to determine the materials' mechanistic behaviour and microstructure characteristics. Emphasis was on examining the effect of various parameters, such as IBA content, enzyme content, moisture content and curing time. Results of this study showed that IBA blends gave a favourable performance as road foundation layers in comparison with the control limestone blend. Microstructure and chemical analysis results showed that the addition of plant-based enzyme improved the mechanical properties of the control limestone blend; however, it did not have any noticeable effect on the IBA blends.

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Understanding the mechanism of interaction of candidate soil stabilizing prototypes by using microscopy and spectroscopy techniques

Ramdas

Lalloo

Lekha

et al. 2021

Microscopy Res & Technique

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Globally, there is a high demand for bio‐based soil stabilizers required for improving the strength properties of weak in situ soil. Microbes and microbial components such as Bacillus spp. have gained interest as soil stabilizers due to their production of spores, bio‐enzymes, and bio‐polymers. However, the current approach for any microlevel assessment of bio‐additives and in situ soil improvement is limited. This paper provides data for microstructural evaluation of stabilized soil material for the postulation of the mode of action. In this study, the microbonding effect (i.e., bio‐based cementation, bio‐clogging, and soil particle bio‐coating) is successfully observed within the various stabilizing prototypes, obtained from a novel Bacillus spp. using advanced methods, namely field emission gun‐scanning electron microscopy and Fourier transform‐infrared spectroscopy. The results show that treated soil versus untreated soil properties are altered by the bio‐additive/s stabilizing effect. These indicator tests provide data for further bio‐stabilizer product prototype development and processes (i.e., improved products in terms of strength and moisture susceptibility). The use of microscopy and spectroscopy was sufficient for the preliminary selection of suitable candidates for soil stabilization.

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Investigation of the effectiveness and mechanisms of enzyme products for subgrade stabilization

Cited by 37 publications

References 3 publications

Life cycle assessment of non-traditional treatments for the valorisation of dry soils in earthworks

Life cycle assessment of non-traditional treatments for the valorisation of dry soils in earthworks

Quantification of the properties of enzyme treated and untreated incinerator bottom ash waste used as road foundation

Understanding the mechanism of interaction of candidate soil stabilizing prototypes by using microscopy and spectroscopy techniques

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