Mechanism of Carbonation in Lime-Stabilized Silty Clay from Chemical and Microstructure Perspectives

Padmaraj, Dhanalakshmi; Arnepalli, Dali Naidu

doi:10.1007/s40891-021-00318-2

Cited by 10 publications

(3 citation statements)

References 45 publications

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“…Otherwise, the carbonation of unreacted lime and pozzolanic products adversely affects the long-term mechanical response [21][22][23]. The effects of lime treatment on unstructured clayey soil with regards to the microstructure, stiffness, shear strength, permeability and durability have been deeply investigated by the pioneering works [14,24,25] and by recent increasingly detailed research [26][27][28][29][30][31][32][33]. However, due to the scale effect of the stabilisation technique, there is a need to test the in situ behaviour of the treated geomaterials employing experimental test embankments [34].…”

Section: Introductionmentioning

confidence: 99%

A Sustainable Option to Reuse Scaly Clays as Geomaterial for Earthworks

Rosone,

Celauro

2024

Geosciences

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Scaly clays are structurally complex clay formations found throughout the world. Their typical fissured structure, the low shear strength and the high swelling potential often make them unsuitable for earthworks in road and railway infrastructure. This research has attempted to extend the possibilities of using this geomaterial in this field after appropriate lime treatment. A laboratory test programme was carried out to evaluate the response of the treated geomaterial to typical loads acting on road infrastructures. Unconfined and confined compression tests as well as cyclic triaxial tests, in undrained conditions, were carried out to investigate the static and dynamic mechanical behaviour. The results show that lime treatment induces significant improvements in the geomechanical properties and limits the swelling behaviour upon saturation of the geomaterial. Dynamic tests showed that, after only 28 days of curing, the treated scaly clay became insensitive to the damaging cyclic loading caused by vehicular traffic. The collected results show that the scaly clay can be properly used as a subgrade and embankment layer in road and railway construction with limited economic and environmental costs, after accurate treatment with lime. These results are significant for researchers and practitioners to increase sustainability in the construction of linear infrastructures involving excavations in scaly clays and to avoid landfill, which in some cases represented the only option.

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Section: Introductionmentioning

confidence: 99%

A Sustainable Option to Reuse Scaly Clays as Geomaterial for Earthworks

Rosone,

Celauro

2024

Geosciences

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“…C. Unluer conducted exploratory, experimental research on simulated sand and silt solidified by MgO carbonization and found that MgO solidified soil has the advantages of a short construction period and high strength compared with cement solidified soil and verified the feasibility of active MgO in the field of soil sample reinforcement [3]. Padmaraj et al studied the carbonization mechanism of lime-stabilized silty clay from the chemical and microscopic perspectives with a lime content of 4% and 8%, and proposed that the carbonization time is too long, which will damage its strength, but this study did not include higher lime dosage samples [4]. E. Vitale et al also proposed that carbonation affects the chemical and mineralogy evolution of lime-treated soil, depending on the time scale of the reaction mechanism, indicating that different slaking times have a great impact on the performance of lime-treated soil [5].…”

Section: Introductionmentioning

confidence: 92%

“…As the reaction continues, the amount of calcium carbonate produced increases, and its strength rises again due to the volume expansion of about 17% during the transformation of calcium hydroxide to calcium carbonate [35], making the soil more compact. However, the higher the lime content, the larger the gel pores of the reaction product [4], and more calcium carbonate can be filled, which is the main reason for the increase in strength of 22.5% doped CaO at 72h of ageing. But as the reaction continues, the continued carbonisation of the calcium hydroxide wrapped around the carbonised product layer will lead to the expansion and cracking of the product layer, producing original microcracks leading to a reduction in strength.…”

Section: Microstructural Analysismentioning

confidence: 99%

Experimental Study on Restoration Materials of Newly Earthen Ruins under Different Slaking Times

Yue

Zhu

et al. 2022

Materials

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The newly repaired Kaifeng City Wall has serious cracks, shedding and other issues on the surface, which constitute a significant problem. It is of great significance for the restoration of Kaifeng City Wall to explore the repair materials and techniques suitable for Kaifeng City Wall. The pH, particle gradation, compressive strength and SEM were tested on soil samples with different lime and MgO contents under different slaking times. With the increase of slaking time, the pH value first increased and then decreased. The relationship between pH value and strength showed three stages. The strength of lime-containing soil samples increased first, then decreased and then increased. The MgO content of soil samples showed an opposite trend. The particle gradation was significantly improved with increasing aging time. The main reason for the reduction of soil strength is the calcium carbonate crystals and magnesite microcracks produced by lime and MgO in the later stage of slaking.

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