Academic literature on the topic 'Stabilised Soil Products'
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Journal articles on the topic "Stabilised Soil Products"
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Sithole, Thandiwe. "Elevated Temperature Basic Oxygen Furnace Slag Stabilisation of Desilicated Foundry Sand." Key Engineering Materials 953 (August 25, 2023): 105–12. http://dx.doi.org/10.4028/p-onlwu9.
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This study presents the use of Basic Oxygen Furnace slag (BOFS) as a stabilizer for disilicated waste foundry (DWF) sand and therefore provides an opportunity for high-volume use of waste material for low-cost, low-volume building and construction material. DWF was stabilized with BOFS to 40 %. The effect of composite moisture content, BOFS content, curing time and curing temperature was studied. A 50:50 DWF: BOFS composite cured at 80 °C for 96 h had the highest unconfined compressive strength (UCS) of 7.83 MPa, a 15.5 % water absorption after a 24 h soak with a corresponding 20.5 % reduction in UCS. The green specimen (70:30) was then used to stabilize expansive soil. The formation of hydration products was responsible for the strength gain in the stabilized DWF specimens. It was concluded that BOFS was successful in stabilizing DFS. The stabilised DWF for ASTM C34-13, C129-14a and South African standards (SANS227: 2007).
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Falciglia, Pietro Paolo, Abir Al-Tabbaa, and Federico G. A. Vagliasindi. "DEVELOPMENT OF A PERFORMANCE THRESHOLD APPROACH FOR IDENTIFYING THE MANAGEMENT OPTIONS FOR STABILISATION/SOLIDIFICATION OF LEAD POLLUTED SOILS." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 22, no. 2 (March 19, 2014): 85–95. http://dx.doi.org/10.3846/16486897.2013.821070.
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Two soils spiked with lead at different rates were stabilised/solidified using Portland cement and fy ash at different soil:binder ratios, and tested for their setting time, unconfined compressive strength, leachability and durability. A performance threshold approach was used in order to identify optimal management options for the products of the S/S treatment. Results show that soil texture, percentage of binders and lead concentration play an important part in the treatment, significantly influencing the performance of the resulting products in terms of curing, compressive strength and durability. Pb soil concentrations higher than 15000 mg kg-1 were found to heavily reduce the applicability of the treatment requiring the maximum amount of binder in order to satisfy the performance criteria. Te performance of sandy soils was shown to be limited by setting time and UCS features due to the retardation of the hydration reactions and also by its leaching behaviour, whereas for silt-clayey soils the critical parameter is the mechanical resistance.
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Jeremiah, Jeremiah J., Samuel J. Abbey, Colin A. Booth, and Anil Kashyap. "Geopolymers as Alternative Sustainable Binders for Stabilisation of Clays—A Review." Geotechnics 1, no. 2 (November 29, 2021): 439–59. http://dx.doi.org/10.3390/geotechnics1020021.
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The need to transit to greener options in soil stabilisation has revamped research on the use of industrial and agricultural by-products in order to cut down on the current carbon footprint from the use of ordinary Portland cement (OPC) and lime related binders for the treatment of problematic soils. This study is a review on the use of geopolymers constituted by alkali activation of several industrial wastes such as pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS), metakaolin (MK), glass powder (GP), palm oil fuel ash (POFA), silica fume (SF), rice husk ash (RHA), volcanic ash (VA), and marble powder (MP) for the stabilisation of weak clays. The performance of stabilised clays as subgrade and subbase materials for road pavement construction was evaluated by comparing the 7 day UCS of the treated clays with the strength requirement for stabilised materials as outlined in BS EN 16907-4. The result of the study shows that geopolymers can be employed in improving the engineering properties of problematic clays to meet practical applications. Strength improvement was observed in the stabilised clays with increased precursor content, molarity of alkaline activator, and curing period.
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Xing, Guoqi, Lijun Zhang, Wei Xuan, Yueyue Pan, Yue Zhao, and Bing Zhang. "Influence of Alkaline Activators on Unconfined Compressive Strength of Saline Soils Stabilised with Ground Granulated Blast Furnace Slags." Advances in Civil Engineering 2021 (November 23, 2021): 1–13. http://dx.doi.org/10.1155/2021/8893106.
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To mitigate the environmental impact induced by CO2 emissions and nonrenewable resource consumption, which are typically associated with Portland cement production, ground granulated blast furnace slags (GGBSs) are usually added to the cement. In this study, the stabilisation effect of alkali-activated GGBS on saline soil and the hydration products of alkali-activated GGBS were investigated by unconfined compressive strength tests and scanning electron microscopy, respectively. The results show that Ca(OH)2 and NaOH as alkaline activators for GGBS significantly improve the unconfined compressive strength of saline soils. This strength is also enhanced by Na2SO4; however, the increase is considerably less than that provided by Ca(OH)2 and NaOH. In contrast, Na2CO3 is not a suitable alkaline activator for GGBS and has no significant effect on the unconfined compressive strength of saline soils. The study results further show that the morphology of hydration products varies because of the different alkaline activators involved in the hydration reaction with GGBS in saline soils.
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Cristelo, Nuno, Jhonathan Rivera, Tiago Miranda, and Ana Fernández-Jiménez. "Stabilisation of a Plastic Soil with Alkali Activated Cements Developed from Industrial Wastes." Sustainability 13, no. 8 (April 18, 2021): 4501. http://dx.doi.org/10.3390/su13084501.
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The development of alternative materials for the construction industry, based on different types of waste, is gaining significant importance in recent years. This is mostly due to the need to increase sustainability of this heavily polluting activity, thus mitigating the dependence on, for instance, Portland cement. The present paper is related to the development of an alkaline activated cement (AAC) exclusively fabricated from industrial by-products (both precursor and activator). Coal combustion fly ash, a common residue from thermoelectric powerplants, and glass waste, from the manufacture of ophthalmic lenses, were used as precursors. These precursors were activated with a recycled alkaline solution, resulting from the cleaning of aluminium extrusion dies, instead of the more common commercial reagents usually applied for this type of binder. Several pastes were studied, combining the precursor and alkaline solution in different proportions. When the most-performing cements were defined, they were used to stabilise a cohesive soil. The experimental procedure and subsequent analysis were designed based on a Response Surface Methodology model, considering the Activator/Solids and Soil/Precursor ratios as the most relevant variables of the stabilisation process. It was observed that, depending on the type of alkaline cement used, there was an optimum precursor and activator contents to optimise the mechanical properties of the stabilised soil. The reliability of this prediction was especially dependent on the type of precursors and, also, on their respective dissolution process right before the homogenization with the soil, under the working conditions available.
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Luo, Zhengdong, Biao Luo, Yufei Zhao, Xinyu Li, Yonghua Su, He Huang, and Qian Wang. "Experimental Investigation of Unconfined Compression Strength and Microstructure Characteristics of Slag and Fly Ash-Based Geopolymer Stabilized Riverside Soft Soil." Polymers 14, no. 2 (January 13, 2022): 307. http://dx.doi.org/10.3390/polym14020307.
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To solve the issues of insufficient early strength of cement stabilized soil and high resource cost, high reduction cost, and high environmental cost induced by the application of cement, the slag and fly ash-based geopolymer was adopted as the stabilizer to treat riverside soft soil. This study mainly investigated the effects of stabilizer content, slag-to-fly ash ratio, and alkaline activator content on the strength of geopolymer stabilized soils with different curing ages. Unconfined compressive strength (UCS), scanning electron microscope (SEM), and X-ray energy spectrum analysis (EDS) tests were carried out. The results show that the stabilizer content, slag–fly ash ratio, and alkaline activator content have a decisive influence on the UCS of geopolymer-stabilized soil. The mix-proportions scheme of geopolymer stabilized riverside soft soil, with a geopolymer content of 15%, a slag–fly ash ratio of 80:20, and an alkaline activator content of 30%, is considered optimum. It is proven by SEM that the uniformly distributed gelatinous products formed in the geopolymer-stabilized soil bind the soil particles tightly. Moreover, the EDS analysis confirms that the gelatinous products are mainly composed of C-S-H gel and sodium-based aluminosilicate (N-A-S-H).
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Shen, Xiao Ming, Zhan Guo Li, Da Huo, and Hai Yan Zhao. "A Preliminary Study of Stabilizing Artificial Saline Sludge Using Compound Stabilizer." Advanced Materials Research 450-451 (January 2012): 343–47. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.343.
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There is large-area saline sludge which should be stabilized in China. In this experiment, cementitious component (cement), alkaline component (Ca(OH)2) and expansive component (sulfuraluminate cement or gypsum) were used as compound stabilizer with different combinations to stabilize artificial saline sludge, then the unconfined compressive strength of stabilized soil samples was determined, and the hydration products of the stabilized soil were analyzed by XRD, the stabilizing mechanism and the required hydrate species of stabilized soil were preliminary explored. The results show that the unconfined compressive strength of stabilized soil increases gradually with the increase of the cement content; when partial cement replaced by right amount of CH, the strength reaches the maximum and higher than that of soil-cement; the use of sulfuraluminate cement plaster as expansive component for stabilizing saline sludge has a relatively good overall affect compared to the gypsum; possible reasons for these results were speculated at the same time.
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Parsons, Robert L., and Justin P. Milburn. "Engineering Behavior of Stabilized Soils." Transportation Research Record: Journal of the Transportation Research Board 1837, no. 1 (January 2003): 20–29. http://dx.doi.org/10.3141/1837-03.
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Stabilization of soils is an effective method for improving soil properties and pavement system performance. For many soils, more than one stabilization agent may be effective, and financial considerations or availability may be the determining factor on which to use. A series of tests was conducted to evaluate the relative performance of lime, cement, Class C fly ash, and an enzymatic stabilizer. These products were combined with a total of seven different soils with Unified Soil Classification System classifications of CH, CL, ML, and SM. Durability testing procedures included freeze–thaw, wet–dry, and leach testing. Atterberg limits and strength tests also were conducted before and after selected durability tests. Changes in pH were monitored during leaching. Relative values of soil stiffness were tracked over a 28-day curing period using the soil stiffness gauge. Lime- and cement-stabilized soils showed the most improvement in soil performance for multiple soils, with fly ash–treated soils showing substantial improvement. The results showed that for many soils, more than one stabilization option may be effective for the construction of durable subgrades. The enzymatic stabilizer did not perform as well as the other stabilization alternatives.
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Liu, Hailong, Jiuye Zhao, Yu Wang, Nangai Yi, and Chunyi Cui. "Strength Performance and Microstructure of Calcium Sulfoaluminate Cement-Stabilized Soft Soil." Sustainability 13, no. 4 (February 20, 2021): 2295. http://dx.doi.org/10.3390/su13042295.
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Calcium sulfoaluminate cement (CSA) was used to stabilize a type of marine soft soil in Dalian China. Unconfined compressive strength (UCS) of CSA-stabilized soil was tested and compared to ordinary Portland cement (OPC); meanwhile the influence of amounts of gypsum in CSA and cement contents in stabilized soils on the strength of stabilized soils were investigated. X-ray diffraction (XRD) tests were employed to detect generated hydration products, and scanning electron microscopy (SEM) was conducted to analyze microstructures of CSA-stabilized soils. The results showed that UCS of CSA-stabilized soils at 1, 3, and 28 d firstly increased and then decreased with contents of gypsum increasing from 0 to 40 wt.%, and CSA-stabilized soils exhibited the highest UCS when the content of gypsum equaled 25 wt.%. When the mixing amounts of OPC and CSA were the same, CSA-stabilized soils had a significantly higher early strength (1 and 3 d) than OPC. For CSA-stabilized soil with 0 wt.% gypsum, monosulfate (AFm) was detected as a major hydration product. As for CSA-stabilized soil with certain amounts of gypsum, the intensity of ettringite (Aft) was significantly higher than that in the sample hydrating without gypsum, but a tiny peak of AFm also could be detected in the sample with 15 wt.% gypsum at 28 d. Additionally, the intensity of AFt increased with the contents of gypsum increasing from 0 to 25 wt.%. When contents of gypsum increased from 25 to 40 wt.%, the intensity of AFt tended to decrease slightly, and residual gypsum could be detected in the sample with 40 wt.% gypsum at 28 d. In the microstructure of OPC-stabilized soils, hexagonal plate-shaped calcium hydroxide (CH) constituted skeleton structures, and clusters of hydrated calcium silicates (C-S-H) gel adhered to particles of soils. In the microstructure of CSA-stabilized soils, AFt constituted skeleton structures, and the crystalline sizes of ettringite increased with contents of gypsum increasing; meanwhile, clusters of the aluminum hydroxide (AH3) phase could be observed to adhere to particles of soils and strengthen the interaction.
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Yi, Yaolin, Kaiwen Lu, Songyu Liu, and Abir Al-Tabbaa. "Property changes of reactive magnesia–stabilized soil subjected to forced carbonation." Canadian Geotechnical Journal 53, no. 2 (February 2016): 314–25. http://dx.doi.org/10.1139/cgj-2015-0135.
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A reactive magnesia (MgO) was used to stabilize a natural soil; the MgO-stabilized soil was subjected to forced carbonation with pressurized gaseous CO2 in a triaxial cell set-up. The change of physical properties, including bulk density, moisture content, dry density, specific gravity, and porosity, of the stabilized soil during carbonation was studied. The mechanical and microstructural properties of the carbonated MgO-stabilized soil were also investigated through unconfined compressive strength (UCS) test, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The results indicated that the carbonation of MgO-stabilized soil consumed CO2 and water, and produced expansive carbonation products; this consequently increased the dry density, and reduced the moisture content, specific gravity, and porosity of the stabilized soil. After being carbonated for only 1.5 h, the MgO-stabilized soil yielded remarkable strength, with UCS higher than that of the 28 day ambient cured Portland cement–stabilized soil, mainly due to the high binding effect of carbonation products and the low porosity of carbonated MgO-stabilized soil. The carbonated MgO-stabilized soil achieved a high degree of carbonation in a few hours (≤12 h), with the maximum CO2/MgO ratio in a range of 0.76–1.07.
Dissertations / Theses on the topic "Stabilised Soil Products"
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Latha, M. S. "Studies on Characteristics of Stabilized Soil Compacts for Structural Applications." Thesis, 2015. https://etd.iisc.ac.in/handle/2005/4502.
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Earth based construction materials are identified as green and low carbon materials. There are sustained R&D efforts in developing stabilised earth products for buildings and other structural applications. The thesis addresses some specific issues on the characteristics of stabilised soil compacts through an extensive experimental R&D work.
Details of three types of stabilised soil products, brief review of literature and scope of the thesis are presented in chapter 1. Chapter 2 is on investigations pertaining to influence of soil grading on the characteristics of cement stabilised soil compacts. Considering wide range of grain size distributions representing two broad soil groups (coarse- and fine-grained soils) influence of soil grading especially the clay size fraction in controlling the strength, durability and absorption characteristics of cement stabilised soil compacts and bricks were examined in greater detail. Optimum soil grading limits yielding maximum strength and the reasons for such behavior was investigated through the analysis of void ratio, surface area porosity and SEM imaging.The investigations showed that clay fraction of the soil mixture and the void ratio (density) of the compacted specimen play crucial role in influencing the characteristics of cement stabilised soil compacts.
Chapter 3 is focused on swell-Shrink characteristics of stabilised soil bricks, adobe bricks and rammed earth. Dimensional changes occurring during the manufacturing process of stabilised soil products were monitored considering the influence of cement content and moulding moisture content. Physical changes such as initial shrinkage, swelling and drying shrinkage occurring during manufacturing process was traced and mapped and the practical significance of the results are discussed.
The main focus of chapter 4 is on effect of aspect ratio of the masonry unit on apparent compressive strength of stabilised soil block and masonry. The anomalies in assessing the characteristic compressive strength of masonry unit while considering the geometrical parameters have been discussed. The shape modification correction factors provided in different codes of practice and reports indicate absence of any unique correction factor accounting for geometry of the masonry unit. Results of compressive strength tests on twelve geometrically different cement stabilised soil bricks/blocks were analyzed in deriving shape modification correction factors. A new definition for aspect ratio based on the surface area of the masonry unit has been proposed. A bi-linear relationship between shape modification correction factor and new aspect ratio has been derived for normalizing the compressive strength of stabilised soil brick/block.
Chapter 5 deals with status of clay minerals in the stabilised soil compacts. The study was aimed at ascertaining the presence of residual clay minerals in the cement and lime stabilised soil compacts. The investigations revealed that it is possible to retrieve a large percentage of natural clay minerals in cement stabilised soil products whereas in lime-stabilised soil products only a small fraction of the clay minerals can be retrieved, as the natural clay gets consumed in the lime-clay reactions. The thesis ends with a summary of the results with concluding remarks and scope for further investigations.
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Silva, Manuela Corrêa Alves. "Stress-strain response of soft soils stabilised with alkali activated industrial by-products." Doctoral thesis, 2021. http://hdl.handle.net/1822/75516.
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Tese de doutoramento em Engenharia CivilAlternative binders based on the alkaline activation technology have been strongly investigated over the last decades as a potential replacement for Portland Cement. However, little research has been devoted to the shear behaviour of soft soils stabilised with those type of binders and their numerical modelling using constitutive models. This PhD thesis aims to deepen the knowledge in this area through the characterisation of the short- and long-term shear behaviour of soft soils stabilised with alkali-activated binders and the numerical modelling of the stress-strain behaviour of these geomaterials using a advanced constitutive model. In this context, triaxial tests were undertaken, after 28 and 90 curing days, in both a sandy lean clay and clay with high water content at reconstituted and stabilised states using alkali-activated blast furnace slags. The impact of the stress-history, represented by the overconsolidation ratio, and stress-state, represented by the initial mean effective stress, were investigated. Oedometer and isotropic consolidation tests were also undertaken. Scanning electron microscopy with energy dispersive spectroscopy, x-ray powder diffraction and leachate analyses were carried out to investigate the nature of the binding phases formed and the risk of contamination of soils. The results were used to calibrate an advanced kinematic hardening constitutive model proposed by Rouainia and Muir Wood, 2000 for natural clays. It was the first attempt of using this constitutive model in artificially cemented soils. Additionally, the opportunity to be integrated within a research project related to the application of alkali-activated industrial wastes in situ allowed me to be deeply involved in constructing a full-scale prototype of a (sub)base layer stabilised with alkali-activated binders and conventional binders. Big challenges arose, including the definition of a construction methodology, equipment selection, on-site handling of distinct materials, quality control techniques, among others. The in situ performance of the stabilised geomaterials was assessed through falling weight deflectometer tests, plate load field tests and unconfined compressive strength tests after 36 and 90 days. For each layer, it was estimated the financial cost of the construction and the equivalent CO2 emissions. The work showed the feasibility of the on-site application of alkali-activated binders in the stabilisation of soil layers in the context of transport infrastructures.
Os ligantes alcalinos têm sido fortemente investigados nas últimas décadas como um potencial substituto do cimento Portland. Contudo, o comportamento ao corte de solos estabilizados com este tipo de ligantes é ainda uma área pouco explorada atualmente, juntamente com o uso de modelos constitutivos. A presente tese de doutoramento visa aprofundar o conhecimento existente nesta área, através da caracterização do comportamento ao corte de solos moles estabilizados com ligantes alcalinos a curto e longo prazo e a modelação numérica do comportamento tensão-extensão desses geomateriais utilizando um modelo constitutivo avançado. Nesse contexto, foram realizados ensaios triaxiais, ensaios edométricos e de consolidação isotrópica, numa argila magra arenosa e numa argila com alto teor em água, ambos no estado reconstituído e estabilizado com escórias de alto-forno ativadas por álcalis, aos 28 e 90 dias de cura. O impacto do grau de sobreconsolidação, representado pela razão de sobreconsolidação, e do estado de tensão in situ, representado pela tensão média efetiva inicial, foram investigados no comportamento ao corte desses geomateriais. Foram realizadas análises de microscopia eletrônica de varrimento com espectroscopia de energia dispersiva e difração de raios-X e testes de lixiviados para investigar a natureza dos géis formados e o risco de contaminação dos solos. Os resultados foram utilizados na calibração de um modelo constitutivo de endurecimento cinemático proposto por Rouainia and Muir Wood, 2000 para argilas naturais que, até ao momento, não tinha sido utilizado em solos artificialmente cimentados. Adicionalmente, a oportunidade de estar integrada num projeto de investigação relacionado com a construção à escala real de uma camada de (sub)base estabilizada com ligantes alcalinos e ligantes convencionais possibilitou-me enveredar por esta temática. Grandes desafios foram encontrados do longo deste projeto, entre os quais, a definição de uma metodologia de construção, a seleção de equipamentos, manuseio dos materiais in situ, definição dos ensaios de controle de qualidade, etc. O desempenho in situ dos geomateriais estabilizados foi avaliado através de ensaios de capacidade de carga com defletómetro de impacto, ensaios de carga em placa e de compressão uniaxial aos 36 e 90 dias. Para cada camada foram também estimados os custos financeiros de construção e as emissões de CO2 equivalentes. Este projeto mostrou a viabilidade de utilização local dos ligantes alcalinos para a estabilização de camadas de solo no contexto das infraestruturas de transporte.
Fundação para a Ciência e a Tecnologia (FCT)
This research work was co-financed by the European Social Fund (FSE) through the Northern Regional Operational Program
Books on the topic "Stabilised Soil Products"
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Logan, T. J. Mine spoil reclamation with sewage sludge stabilized with cement kiln dust and flue gas desulfurization by product (N-viro soil process). S.l: s.n, 1992.
Find full textBook chapters on the topic "Stabilised Soil Products"
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Duong, Thanh Nga, Tomoaki Satomi, and Hiroshi Takahashi. "Study on Strength of Modified Sludge Produced By Fiber-Cement Stabilized Soil Method Using Several Kinds of Fiber Materials." In Lecture Notes in Civil Engineering, 580–87. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-6713-6_57.
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Sposito, Garrison. "Oxidation– Reduction Reactions." In The Chemistry of Soils. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780190630881.003.0010.
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Soils become flooded occasionally by intense rainfall or by runoff, and a significant portion of soils globally underlies highly productive wetlands ecosystems that are inundated intermittently or permanently. Peat-producing wetlands (bogs and fens) account for about half the inundated soils, with swamps and rice fields each accounting for about one-sixth. Wetlands soils hold about one-third of the total nonfossil fuel organic C stored below the land surface, which is about the same amount of C as found in the atmosphere or in the terrestrial biosphere. This C storage is all the more impressive given that wetlands cover less than 6% of the global land area. On the other hand, wetlands ecosystems are also significant locales for greenhouse gas production. They constitute the largest single source of CH4 entering the atmosphere, emitting about one-third the global total, with half this amount plus more than half the global N2O emissions coming from just three rice-producing countries. A soil inundated by water cannot exchange O2 readily with the atmosphere. Therefore, consumption of O2 and the accumulation of CO2 ensue as a result of soil respiration. If sufficient humus metabolized readily by the soil microbiome (“labile humus”) is available, O2 disappearance after inundation is followed by a characteristic sequence of additional chemical transformations. This sequence is illustrated in Fig. 6.1 for two agricultural soils: a German Inceptisol under cereal cultivation and a Philippines Vertisol under paddy rice cultivation. In the German soil, which was always well aerated prior to its sudden inundation, NO3- is observed to disappear from the soil solution, after which soluble Mn(II) and Fe(II) begin to appear, whereas soluble SO42- is depleted (left side of Fig. 6.1). The appearance of the two soluble metals results from the dissolution of oxyhydroxide minerals (Section 2.4). Despite no previous history of inundation, CH4 accumulation in the soil occurs and increases rapidly after SO42- becomes undetectable and soluble Mn(II) and Fe(II) levels have become stabilized. During the incubation time of about 40 days, the pH value in the soil solution increased from 6.3 to 7.5, whereas acetic acid (Section 3.1) as well as H2 gas were produced.
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Keefer, Robert F. "Soil Organic Matter." In Handbook of Soils for Landscape Architects. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195121025.003.0018.
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Soil organic matter (SOM) is probably the most important constituent of soils. The effect of SOM on soil properties far exceeds the relative percentage of this material in soils. The small amount of organic matter in soils, usually from 1 to 5%, is very important in providing a reserve food source for microorganisms and higher plants. Almost all properties of SOM are beneficial for plant growth. Soil organic matter can be defined as a complex, heterogeneous mixture of plant and animal remains in various stages of decay, microbial cells—both living and dead—microbially synthesized compounds, and derivatives of all of the above through microbial activity. Soil organic matter is probably the most complex of all naturally occurring substances. Some compounds in SOM are distinctive to soil and are not present in plants or animals. By examining the composition of SOM, one can see why it is such a complex material. The following compounds have been isolated from chemical SOM extracts: . . . 1. Carbohydrates (sugars, polysaccharides)—about 75% of dry weight 2. Lignin (a plant polymer of phenyl propane units) 3. Proteins (combinations of amino acids) 4. Hydrocarbons—fats, waxes, resins, and oils 5. Tannins (phenolic substances) 6. Pigments (chlorophyll) 7. Organic acids (many in the biochemical Krebs cycle) 8. Miscellaneous compounds—includes organic P, organic S, polynuclear hydrocarbons, nucleic acid derivatives, alcohols, aldehydes, esters, etc. . . . Whenever organic materials are added to a soil the physical properties of soil structure, water-holding capacity, and soil color are changed. The extent of change in these properties depends on the amount and type of organic material added, the soil microorganisms present in the soil, and the speed at which decomposition occurs. Aggregation and granulation (crumb formation) is increased by polysaccharides produced by microorganisms during decomposition. This improves soil tilth (ability to work the soil) and helps stabilize the soil crumbs. The ability of a soil to hold water is greatly increased by addition of SOM. This results in greater infiltration (water moving into the soil) and adsorption of water by the SOM, with consequently less erosion and loss of soil particles and fertility.
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Lazcano, Cristina, Charlotte Decock, Connie T. F. Wong, and Kamille Garcia-Brucher. "Assessing the effects of compost on soil health." In Improving soil health, 221–80. Burleigh Dodds Science Publishing, 2022. http://dx.doi.org/10.19103/as.2021.0094.06.
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As agricultural producers embrace the principles of the circular economy and regenerative practices, the use of organic fertilizers is becoming increasingly common. Composting is a robust, low-cost technology that stabilizes organic waste materials into organic fertilizers that can be safely applied to crops. Numerous experiments carried out in the last decades show that compost has well-known short- and long-term, direct, and indirect benefits for soil health, albeit these are extremely variable. This uncertainty may decrease grower adoption rates. This chapter provides a critical evaluation of the potential of compost to improve soil health. Looking at a wide range of soil health indicators, we identify those that are consistently responsive to compost. We identify sources of variability and potential risks of compost for environmental quality, pointing at future research needs. Two case studies evaluate the tradeoffs between benefit and risks in the use of compost in perennial and annual crops.
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Yadav, Virendra Kumar, and Priti Raj Pandita. "Fly Ash Properties and Their Applications as a Soil Ameliorant." In Advances in Environmental Engineering and Green Technologies, 59–89. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7940-3.ch005.
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Fly ash is one of the major global pollutants which is produced in millions of tons every year. The high content of heavy metals in fly ash categorizes them as hazardous materials. The presence of ferrous, alumina, and silica along with numerous macro- and micro-nutrients make them a suitable candidate for applications in agriculture, forestry, wasteland reclamation, soil stabilizer, etc. Fly ash has positive effects on the plant growth and crop yield. A numerous literature has reported the applications of fly ash as pesticides, herbicides, and insecticides. It has both alkaline and acidic pH which helps in maintaining the pH of the infertile soil. All these applications are cited with the previous work carried out by the investigators.
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Sheikhavandi, Tarlan. "Microbial Functional Activity in Bioremediation of Contaminated Soil and Water." In Handbook of Research on Uncovering New Methods for Ecosystem Management through Bioremediation, 286–315. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8682-3.ch012.
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Since the beginning of the industrialization, application of chemical compounds on lands and disposal of contaminants to soil and water systems have caused numerous sorts of alterations in environment, and therefore affected the inhabitant biodiversity. This chapter aims to provide an introduction to bioremediation, an innovative multidisciplinary technology which employs microorganisms in order to reduce, eliminate, contain or transform hazardous contaminants in soil, sediment or water. So far, microorganisms and plants have been utilized to breakdown or transform several contaminants into less toxic forms. Main focus of chapter will be on several bioremediation techniques, employing indigenous microorganisms to decompose biodegradable pollutants in order to stabilize or to transform the contaminants into non-hazardous by-products. Besides, it will elucidate several factors effecting bioremediation process, involving energy source as a dominant necessity of microbial activity. Undoubtedly, bioremediation offers a greener pathway of remediation in comparison with wide varieties of conventional and artificial treatments.
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Zamanian, Kazem, and Yakov Kuzyakov. "Soil inorganic carbon: stocks, functions, losses and their consequences." In Understanding and fostering soil carbon sequestration, 209–36. Burleigh Dodds Science Publishing, 2022. http://dx.doi.org/10.19103/as.2022.0106.07.
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Carbonate-containing minerals comprise an additional form of soil carbon known as soil inorganic carbon (SIC). Though SIC stocks are large, they been disregarded in most studies to carbon sequestration. After reviewing the main forms of SIC (geogenic, biogenic and pedogenic carbonates) and the chemical processes leading to formation of pedogenic carbonates, we review the importance of SIC in the global C cycle and ecosystem functions. Besides pH regulation, SIC and dissolved Ca2+ from carbonates dissolution: i) increase plant growth due to better root growth, nutrient availability and acquisition, as well as provide protection against pathogens; ii) increase activities of soil microorganisms mineralizing nutrients; and iii) bind organic compounds which, consequently, stabilize organic matter, produce larger and stable aggregates, and control water permeability and balance. Consequently, the SIC is crucial not only for pH regulation, but also strongly contributes to many other soil functions and health. Finally, we assess future SIC losses under anticipated global change processes such as increased N deposition and fertilization, elevated CO2, invasive plant distribution and climate change. These SIC losses damage soil functionality and make it more vulnerable to a broad range of degradation factors, including erosion, topsoil and subsoil compaction, acidification and nutrient depletion. Crucial is that in contrast to organic carbon, the SIC losses are irrecoverable. We conclude that SIC is an important soil constituent responsible for a broad range of physical, chemical and biological soil properties and processes as well as ecosystem services such as cycles of C, N and other elements.
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Montagnini, Florencia. "Nutrient Considerations in the Use of Silviculture for Land Development and Rehabilitation in the Amazon." In The Biogeochemistry of the Amazon Basin. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195114317.003.0010.
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Tropical plantations serve diverse economic, social, political, and ecological functions. With considerably higher yields than managed native forests, tropical and subtropical plantations make substantial contributions to world timber and pulp production (Wadsworth 1983, Evans 1992). Tree plantations can also be a source of cash, savings, and insurance for individual farmers. Plantations may help stabilize rural populations in regions where shifting agriculture is the predominant land use. In combination with subsistence and commercial crops (agroforestry) or cattle (agrosilvopastoral systems), plantations have been used as tools in rural development projects worldwide. Plantations are often seen as alternatives to deforestation as they can provide products that otherwise would be taken from natural forests (Fearnside 1990, McNabb et al. 1994). Nutrient cycling characteristics of tropical plantations differ from those of natural forests in a number of ways. Natural forests are adapted to ecological niches by intricate and effective physiological adaptations of growth in the environment (see Cuevas, this volume). Instead, tropical plantations are simplified, generally monospecific ecosystems that occupy the site for a limited period of time that can range from 4-12 years (for biomass, pulpwood, or fuelwood) up to 20-40 years (timber). In many instances plantations are composed of species that are exotic to the region, or even when indigenous, are new to the particular plantation site. Since plantation tree species have been generally selected for production of timber or other aboveground tree parts, they tend to maintain a smaller fraction of total tree biomass nutrients in roots than natural forests (Vogt et al. 1997). In rain forests growing on poor soils, high tree productivity is in part due to the existence of important nutrient conserving mechanisms mediated by the root system (Cuevas, this volume). The smaller biomass of plantation root systems may thus make them more susceptible to nutrient and water stress. Smaller root systems may also make plantation forests more susceptible to disturbances from strong winds and pathogens that attack aerial parts (Vogt et al. 1997). Nutrient demands by plantation trees vary from season to season and with the developmental age of the stand (Drechsel and Zech 1993). During the life of the plantation, large quantities of nutrients are returned to the soil by above- and belowground litter, harvest residues, stem flow, and throughfall.
Conference papers on the topic "Stabilised Soil Products"
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Kong, Gang-qiang, Qing Yang, and Mao-tian Luan. "Study on Negative Skin Friction of Pile Groups Considering Coupled Effect of Surface Load and Soil Consolidation." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79679.
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The study was performed based on an analysis of model test results of 3×3 pile group and confirmed the reliability and accuracy of determining negative skin friction (NSF) using numerical modeling of fluid-soild interaction. A 3D numerical model with surface load and soil consolidation was established using FLAC3D, which focused on the mechanism of NSF and its influence factors such as friction of pile-soil interface, spacing of pile and time of consolidation. The results obtained under different cases in an engineering practice were finally compared with measured and empirical data, showing that it is necessary to consider surface load and soil consolidation when dealing with NSF. The results also indicated the analysis with surface load and soil consolidation could simulate the developing process of NSF and produce a more accurate outcome — closer to measured data. The NSF increases rapidly at beginning and then slowly down, finally stabilized at a constant as soil consolidation progresses. Due to pile group effects, the piles at the centre had a smaller downdrag and settlement than those at corner or at edges; pile group effects became more obvious when pile spacing decreased.
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Tannoury, George A., and Steven D. Schrock. "Introduction to Chemical Stabilization of Unstable Trackbeds." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5779.
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Trackbeds are typically composed of all granular materials comprised of ballast and subballast over compacted subgrade. Most poor performances of railroads can be attributed to poor and unstable subgrade conditions. Below the surface, the instability of the subgrade material can propagate through the granular zone leading to excessive settlements and deformations of the railway. Conventional subgrade restoration in the trackbed system requires the removal of the granular materials and over-excavation of soft unstable subgrade materials, moisture adjustment, re-compaction, and sometimes chemical stabilization of the subgrade soils. Since these procedures are considered very expensive in terms of construction equipment, railway outage time, and labor force, alternative solutions for consideration and evaluation are essential. Injection of expansive foam (polymer based) materials is a relatively recent method that has been used in various applications of soil stabilization in the roadway industry. This technique relies on the injection of rigid-polyurethane foam, which is a high-density, expanding, thermoset, hydro-insensitive and environmentally neutral polyurethane-resin product, into the soft and unstable soil to improve their shear strength and stability index. In addition, the stabilized zone acts as a waterproof membrane protecting moisture sensitive subgrade, and acting as a separation layer to eliminate pumping and contamination of the granular subballast at saturated fine grained conditions. The objective of this paper is to evaluate the practicability of polyurethane stabilized soft and unstable subgrade under unbounded granular trackbeds to mitigate future deformation, restore railway foundation, and reduce trackbed repair cost and outage time.
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Okoro, Chibuikem C., John Vogtman, Ahmad Yousif, Mohammed Agnaou, and Naji Khoury. "Consolidation Characteristics of Soils Stabilized with Lime, Coal Combustion Product, and Plastic Waste." In Geo-Frontiers Congress 2011. Reston, VA: American Society of Civil Engineers, 2011. http://dx.doi.org/10.1061/41165(397)123.
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Kulshreshtha, Yask, Philip J. Vardon, Gabrie Meesters, Mark C. M. van Loosdrecht, Nelson J. A. Mota, and Henk M. Jonkers. "What Makes Cow-Dung Stabilised Earthen Block Water-Resistant." In 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.540.
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The water-resistance of cow-dung has made it a widely used stabiliser in traditional earthen structures in several Asian and African countries. Multiple studies have shown an improvement in water-resistance with the addition of cow-dung, but none provides insight into this behaviour. The present study investigates the water-resistance behaviour of cow-dung stabilised earthen blocks through an extensive experimental programme to identify and characterise the components of cow-dung responsible for its water-resistance. Fresh cow-dung was collected and separated into fibres (>63 μm), medium-sized microbial aggregates (1-63 μm) and small-sized microbial aggregates (0.5-7 μm). Each component was mixed with soil and samples were prepared at different water contents (optimum water content corresponding to the highest dry density and water content higher than optimum) and compacted with 2.5 MPa force to prepare compressed blocks. The water-resistance of these blocks was evaluated through the immersion and modified drip/rain test. It was found that the small-sized microbial aggregates are almost entirely responsible for water-resistance behaviour of cow-dung stabilised earthen blocks. Small-sized microbial aggregates were further characterised by gas chromatography, mercury intrusion porosimetry, N2- BET surface area, zeta potential measurement and electron microscopy. The results indicate that the small-sized microbial aggregates are composed of clay-sized negatively charged particles that are rich in fatty acids. The hydrophobicity of these particles is hypothesised to be responsible for water-resistance behaviour. These insights are further used to produce stabilised blocks that performed at least 30 times better than the unstabilised blocks in both water-resistance tests. The study concludes with practical recommendations for the use of wet cow-dung over dry cow-dung and a reduction of fibre content to increase the water-resistance of earthen blocks.
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Seniunaitė, Jurgita, and Saulius Vasarevičius. "Heavy Metals Leaching of MSWI Bottom Ash: Effect of Short-term Natural Weathering." In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.046.
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Municipal solid wastes incineration (MSWI) is an important part of the waste management systems in many European countries. Incineration process generates two main by-products: fly ash (FA) and bottom ash (BA). Bottom ash is composed of a variety of oxides, heavy metals and salts. Landfilling of untreated (fresh) BA can cause soil, surface and ground water contamination problems, because atmospheric precipitation in BA formed leachate, which contains of various materials. In this study investigates the influence of natural weathering to heavy metals leaching from BA. Leaching tests of bottom ash were carried out in 6 months, leachate samples were taken at 12 times (every 2 weeks). Heavy metals (Pb, Cu) concentrations were determined by atomic adsorption of spectral analysis method. The research shown, that the highest lead and copper concentration was determinated in 2 weeks weathered bottom ash leachate, respectively was 0.613 mg l–1 and 0.068 mg l–1. In both cases the concentration of Pb (0.010–0.052 mg l–1) and Cu (0.010-0.018 mg l–1) became almost stable after 12 weeks. Can be concluded, that short-term (3 months) natural weathering is sufficient time for stabilise MSWI bottom ash and heavy metals (Cu and Pb) leaching. After 18–24 weeks heavy metals concentrations stabilized and remained almost constant.
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Yang, Bo, Halil Ceylan, Kasthurirangan Gopalakrishnan, and Sunghwan Kim. "Evaluation of the Freeze and Thaw Durability of Road Soils Stabilized with a Biofuel Co-Product." In Geotechnical Frontiers 2017. Reston, VA: American Society of Civil Engineers, 2017. http://dx.doi.org/10.1061/9780784480441.014.
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Losini, Alessia Emanuela, Liudmila Lavrik, Marco Caruso, Monika Woloszyn, Anne Cecile Grillet, Giovanni Dotelli, and Paola Gallo Stampino. "Mechanical Properties of Rammed Earth Stabilized with Local Waste and Recycled Materials." In 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.113.
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Traditional techniques of construction using natural and locally available materials are nowadays raising the interest of architects and engineers. Clayey soil is widely present in all continents and regions, and where available it is obtained directly from the excavation of foundations, avoiding transportation costs and emissions due to the production of the binder. Moreover, raw earth is recyclable and reusable after the demolition, thanks to the absence of the firing process. The rammed earth technique is based on earth compressed into vertical formworks layer by layer to create a wall. This material owes its strength to the compaction effort and due to its manufacture procedure exhibits layers resembling the geological strata and possessing high architectural value. The hygroscopic properties of rammed earth allow natural control of the indoor humidity, keeping it in the optimal range for human health. Stabilization with lime or cement is the most common procedure to enhance the mechanical and weather resistance at once. This practice compromises the recyclability of the earth and reduces the hygroscopic properties of the material. The use of different natural stabilizers, fibers, and natural polymers by-products of the agriculture and food industry, can offer an alternative that fits the circular economy requirements. The present study analyses the mechanical strength of an Italian earth stabilized with different local waste and recycled materials that do not impair the final recyclability of the rammed earth.
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Musso Laespiga, Marcos, and Leonardo Behak Katz. "Performance of Low-Volume Roads with Wearing Course Layer of Silty Sandy Soil Modified with Rice Husk Ash and Lime." In CIT2016. Congreso de Ingeniería del Transporte. Valencia: Universitat Politècnica València, 2016. http://dx.doi.org/10.4995/cit2016.2016.3451.
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Rice husk ash (RHA) is a by-product of rice milling. Its use as soil stabilizer is a way to replace the final disposal with environmental benefit. However, RHA is not cementitious itself but when mixed with lime forms cements which improve the soil properties. A research of performance of a silty sandy soil modified with RHA and lime as wearing course layer of low-volume roads was conducted through two full-scale test sections with different pavements built in Artigas, northern Uruguay. The alkaline reactivity of RHA is low because the husk burning is not controlled. The soil-RHA-lime mix design was conducted according to the Thompson’s Method. The pavement test sections were monitored through deflection measures by Benkelman beam and observations of surface condition. The deflections decreased over time in both test sections due to the development of cementation of the study materials. After one year, the dust emission was reduced, the wet skid resistance of pavement surfaces improved and there was not rutting. The researched pavements have had a good performance under the existing traffic and environmental conditions, demonstrating that wearing course layer of silty sand modified with RHA and lime is an alternative to improve the condition of low-volume roads and to replace the final disposal of RHA, with environmental, social and economic benefits.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3451
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Rose, L., Z. Tang, A. Burgess, and O. Kesler. "Improvement of Plasma Sprayed Yttria Stabilized Zirconia (YSZ) Electrolytes for Solid Oxide Fuel Cells by Spin Coated Sol Gel Solutions." In ITSC2007, edited by B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and G. Montavon. ASM International, 2007. http://dx.doi.org/10.31399/asm.cp.itsc2007p0478.
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Abstract Yttria stabilized zirconia (YSZ) is the most commonly used electrolyte material for solid oxide fuel cells (SOFCs), due to its pure ionic conductivity and chemical stability. Standard electrolyte fabrication techniques for planar fuel cells involve wet ceramic techniques such as tape-casting or screen printing, which require sintering at temperatures above 1300°C. Plasma spraying (PS) may provide a more rapid and cost efficient method of producing SOFCs without requiring high temperature post-deposition heat treatments. However, it is difficult to produce plasma sprayed layers that are both thin (<20µm) and completely dense. It is of utmost importance to have a dense electrolyte to prevent the mixing of cathode and anode reactant gases. This study investigates the use of spin coated sol gel derived YSZ precursor solutions to fill the pores present in plasma sprayed YSZ layers.
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Lage, Gabriela Tavares de Lanna, White José dos Santos, and Sofia Araújo Lima Bessa. "Use of iron mining tailings in rammed earth: a literature survey." In ENSUS2023 - XI Encontro de Sustentabilidade em Projeto. Grupo de Pesquisa Virtuhab/UFSC, 2023. http://dx.doi.org/10.29183/2596-237x.ensus2023.v11.n4.p308-320.
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The Minas Gerais region is recognized as one of Brazil's largest iron ore extraction areas, the world's second-largest producer. During mineral extraction, tons of tailings are generated and stored in dams. In parallel, a challenge in the Civil Engineering and Architecture sector is presenting construction solutions with a lower environmental impact. Among these, rammed earth is a construction technique with great sustainable potential due to the possibility of lower embodied energy than conventional techniques. Because of this possibility of interaction, this paper proposes to analyze the potential use of iron ore tailings (IOT) as a physical stabilizer, acting as a granulometric corrector of rammed earth. No investigations were found regarding using RMF in rammed earth in civil construction. It was found that it is possible that the use of IOT may be viable for soil size correction in rammed earth or as a substitute for base material. This is due to the physical, chemical, and mineralogical characteristics of RMF being suitable for this technique, especially when sand, fine sand, or silt percentages are required.
Reports on the topic "Stabilised Soil Products"
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Fuchs, Marcel, Jerry Hatfield, Amos Hadas, and Rami Keren. Reducing Evaporation from Cultivated Soils by Mulching with Crop Residues and Stabilized Soil Aggregates. United States Department of Agriculture, 1993. http://dx.doi.org/10.32747/1993.7568086.bard.
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Field and laboratory studies of insulating properties of mulches show that the changes they produce on the heat balance and the evaporation depend not only on the intrinsic characteristics of the material but also on the structure of air flow in boundary layer. Field measurements of the radiation balance of corn residue showed a decrease of reflectivity from 0.2 to 0.17 from fall to spring. The aerodynamic properties of the atmospheric surface layer were turbulent, with typical roughness length of 12 to 24 mm. Evaporation from corn residue covered soils in climate chambers simulating the diurnal course of temperature in the field were up to 60% less than bare soil. Wind tunnel studies showed that turbulence in the atmospheric boundary layer added a convective component to the transport of water vapor and heat through the mulches. The decreasing the porosity of the mulch diminished this effect. Factors increasing the resistance to vapor flow lowering the effect of wind. The behavior of wheat straw and stabilized soil aggregates mulches were similar, but the resistance to water of soil aggregate layer with diameter less than 2 mm were very large, close to the values expected from molecular diffusion.
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Butler, Afrachanna, Catherine Thomas, Nathan Beane, Anthony Bednar, and William Frederick. Phytomanagement of soil and groundwater at the Niagara Falls Storage Site (NFSS) using hybridized trees. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42083.
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The Manhattan Engineer District previously used the 191-acre Niagara Falls Storage Site (NFSS) in Niagara County, New York, to store radioactive residues and wastes from uranium (U) ore processing. At present, management practices will determine whether enhanced evapotranspiration rates produced by hybridized shrub willow cuttings planted in 2016 will affect groundwater hydrology. Two shrub willow varieties were planted in an approximately one-half acre area to examine growth performance along a U impacted sanitary sewer line. Additionally, control plots will compare the effectiveness of shrub willows to unplanted areas. Observations of the planted area after 18 months showed success of shrub willow growth with increasing biomass. Chemical analysis from tree tissue samples of the field study showed no significant uptake of U or thorium (Th) to date. A greenhouse study conducted in parallel to the field study tested the willows under controlled greenhouse conditions and evaluated their ability to grow and accumulate contaminants under controlled conditions. Results from the greenhouse study demonstrated that U accumulation was minimal. Thus, this study demonstrates that the shrub willows are not accumulators of U or Th, an advantageous characteristic that implies stabilized contaminants in the soil and no translocation of U into the aboveground biomass.