Stabilization of Expansive Clayey Soil with Alkali Activated Binders

Syed, Mazhar; GuhaRay, Anasua; Kar, Arkamitra

doi:10.1007/s10706-020-01461-9

Cited by 35 publications

(10 citation statements)

References 43 publications

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“…The structure of the samples predominantly consisted of pores, hollow cavities, and unreacted/partially dissolved fly ash cenospheres. This is in agreement with the findings of Jaditager and Sivakugan [66] and Syed et al [53], who found pores in the stabilised soil at an early age. NASH cementitious products or geopolymer gels were also observed around the fly ash and clay particles in several parts of the samples; however, more cementitious products were formed with the increase in the fly ash content.…”

Section: Scanning Electron Microscopysupporting

confidence: 93%

“…This 'featureless hump' indicated the newly precipitated compounds due to the geopolymerisation as described by Duxson et al [13]. The new amorphous geopolymer phase detected at 2θ values of 12-28° indicated the formation of NASH gel [53,[60][61][62][63]. On the other hand, no new crystalline phase was observed in the stabilised soil.…”

Section: X-ray Diffraction Analysismentioning

confidence: 58%

“…The UCS results of the soils stabilised with alkali-activated fly ash showed insignificant improvement at 1 day of curing. This can be attributed to the fact that the alkali activators have low reactivity with Si and Al in fly ash in the initial phase [53]. Parhi et al [54] argued that the curing time is needed for the reaction to occur and for the products of the reaction derived from the dissolution of Al and Si minerals to accumulate.…”

Section: Effects Of Curing Time On Ucsmentioning

confidence: 99%

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Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay

2022

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This study investigated the improvement in the behaviour of a clay soil due to the addition of alkali-activated fly ash as a stabilising agent, and the effects of different activation factors such as alkali dosages and silica moduli. The alkali activator solution used was a mixture of sodium silicate and sodium hydroxide. Class F fly ash was used as the precursor material for the geopolymerisation process. Soil samples stabilised with non-activated class F fly ash were prepared and tested to compare the results with samples stabilised with alkali-activated fly ash. Compaction tests, unconfined compressive strength tests, X-ray diffraction analysis, and scanning electron microscopy analysis were carried out on samples cured 1, 7, and 28 days at room conditions. The results showed that the compressive strength of stabilised soil significantly increased when the fly ash was activated. The optimal activation parameters to stabilise the soil were found to be alkali dosages in the range of 12% to 16% and a silica modulus of 1.25. The highest compressive strength recorded was at 1293 kPa with an alkali dosage of 16% and a silica modulus of 1.25, while for the non-stabilised soil, it was at 204 kPa at 28 days of curing. Mineralogical analysis showed a decrease in the peak intensities of kaolinite and illite, while microstructural analysis indicated an alteration in soil texture with the addition of the alkali-activated fly ash.

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Section: Scanning Electron Microscopysupporting

confidence: 93%

Section: X-ray Diffraction Analysismentioning

confidence: 58%

Section: Effects Of Curing Time On Ucsmentioning

confidence: 99%

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Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay

2022

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“…The stabilization of clay soil by means of geopolymerization would improve the mechanical strength (UCS, CBR, etc.). For the alkaline activation of fly ash, sodium hydroxide and sodium silicate are the best combinations [20][21][22]. The modular ratio (sodium silicate /sodium hydroxide) is greater than 1.5 strength of stabilized soil decreases [16].…”

Section: Introductionmentioning

confidence: 99%

Partial Replacement of Conventional Material with Stabilized Soil in Flexible Pavement Design

2022

IJE

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Due to rapid urbanization and industrialization, the construction of roads increases rapidly for easy and fast transportation. Adequate land is not available everywhere to construct good roads; hence, roads are forcefully built on locally available soil such as loose soil or expansive soil. In this paper, an experimental investigation was carried out on low plastic soil (LPS) to enhance engineering properties by using chemical soil stabilization (fly ash-based geopolymer). The design of flexible pavement thickness was carried out for conventional and stabilized soil material using IITPAVE software as per IRC 37 guidelines. The results show the feasibility of fly ash-based geopolymer significant enhancement of strength were observed in terms of unconfined compressive strength (UCS) for various curing days (0 to 128 days), California bearing ratio (CBR), and Resilient modulus (MR). The microstructural analysis via Scanning Electronic Microscope (SEM) and X-Ray Diffraction Analysis (XRD) was also reveling the formation of geopolymeric gel which leads to the dense matrix to soil mass. The flexible pavement thickness significantly reduces with the application of stabilized low plastic soil.

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“…This was related to the chemo-physical evolution of the binders over curing time using X-Ray Diffraction (XRD) analysis. Syed et al [29] used NaOH and Na 2 SiO 3 -activated Class F fly ash to treat an expansive soil (black cotton soil) and assessed the success of the treatments in terms of California Bearing Capacity Ratio (CBR) and Unconfined Compressive Strength (UCS) increase. Pourakbar et al [16] activated locally available palm oil fuel ash as precursor using NaOH and KOH, and successfully used it for the treatment of a clayey soil in terms of increase in UCS and ultimate bearing capacity.…”

Section: Introductionmentioning

confidence: 99%

A Study of Innovative Alkali-Activated Binders for Soil Stabilisation in the Context of Engineering Sustainability and Circular Economy

et al. 2021

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In the context of sustainability in the civil engineering industry, chemical ground improvement is becoming increasingly used, as a generally more sustainable alternative to replacing and landfilling unsuitable for construction ground. However, traditional soil stabilisers such as Portland cement or lime are not environmentally impact-free; international research effort is thus focusing on the development of innovative cementing agents. This paper presents results from a feasibility study on the development of suitable alkali-activated slag cements for the stabilisation of two soils. A number of alkali-activators were considered, comprising potassium hydroxide, a range of alkali salts, as well as a material retrieved from waste (Paper Sludge Ash, PSA) which contains free lime. Indicative results of an extensive parametric study in terms of unconfined compressive strength (UCS) are shown, followed by results of ongoing oedometer tests to determine soil compressibility and some preliminary tests on selected soil/binder mixes to observe the durability to wetting-drying cycles. Overall, all alkali-activated cement mixes increased the UCS and stiffness of the soil. Carbonates and Na2SiO3 used on their own gave lower strength increases. The highest strengths were achieved from AAC with KOH and Ca(OH)2 from PSA, which showed similar strength gain. The latter material has shown consistently a lot of promise in terms of strength, stiffness and volumetric stability of the soil as well as treatment durability. Ongoing research focuses on further mix optimisation and a comprehensive mechanical and durability property testing supported by material analysis (mineralogical, chemical and microstructural) to gain a better understanding of the complex mechanisms involved.

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Stabilization of Expansive Clayey Soil with Alkali Activated Binders

Cited by 35 publications

References 43 publications

Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay

Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay

Partial Replacement of Conventional Material with Stabilized Soil in Flexible Pavement Design

A Study of Innovative Alkali-Activated Binders for Soil Stabilisation in the Context of Engineering Sustainability and Circular Economy

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