Study on Strength Development and Microstructure of Cement-Solidified Peat Soil Containing Humic Acid of Dianchi Lake

Cao, Jing; Huang, Siyang; Liu, Wenlian; Gao, Yue; Song, Yunfei; Li, Songpo

doi:10.1155/2022/8136852

Cited by 8 publications

(8 citation statements)

References 12 publications

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“…This was accompanied by an increase in the internal pore amounts and pore size, and a corresponding decrease in the compactness of the solidified soil structure. These findings are consistent with those of other researchers [34][35][36]. Additionally, the results indicate that the most probable aperture was affected by soil characteristics.…”

Section: Pore Analysissupporting

confidence: 93%

Dry-wet cycles durability of solid waste based cementing materials solidifying different characteristic soils

Zeng,

Shu,

Qiu

et al. 2024

Mater. Res. Express

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A comparative study of the durability of multi-source solid waste-based soil solidification materials in solidifying different soil types has not yet been conducted. Therefore, the properties of multi-source solid waste-based solidification materials (SBM) solidifying clay soil (CS), sandy soil (SS) and organic soil (OS) subjected to dry-wet cycles of damage were studied in this work. The unconfined compressive strength (UCS) of the SBM solidified soil was tested to evaluate the mechanical properties of the solidified soil. Scanning electron microscopy (SEM) and mercury injection porosimetry (MIP) tests were conducted in order to study the micro-action mechanism. The results demonstrated that the SBM showed wide applicability and good long-term performance. The rate of strength increase of the SBM solidified soil during the long-term curing period was found to be dependent on soil characteristics. All the types of SBM solidified soils exhibited increased UCS during the first 10 cycles of the D-W. As the number of D-W cycles increased from 10 to 50, the UCS loss rate for CS reached 78%, with OS experiencing the least at 58%. The structure of SBM solidified soil exhibited softening and weakened resistance to deformation with each additional D-W cycle. The types of hydration products were consistent across all three soil types. The quantity of hydration products was influenced by the characteristics of the soil, which also contributed to the deterioration of damage resistance in D-W cycles. The number of pores within the SBM solidified soil increased with the number of D-W cycles (>10 cycles), resulting in a deterioration of the compact structure.

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Section: Pore Analysissupporting

confidence: 93%

Dry-wet cycles durability of solid waste based cementing materials solidifying different characteristic soils

Zeng,

Shu,

Qiu

et al. 2024

Mater. Res. Express

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“…Generally, a small amount of gypsum is added to OPC to avoid some negative effects caused by the fast hydration reaction of C 3 A. Gypsum's presence causes the formula's chemical reaction (9) to form ettringite (AFt). The hydration product cements the soil particles and fills the pores between the particles.…”

Section: Mip Results and Analysismentioning

confidence: 99%

“…Because of its many advantages, the cemented soil mixed method is often used in engineering [4][5][6][7]. The Quaternary sediments in the Dianchi Lake area are deep and the widely distributed peat soil have brought many problems to the economic construction of Kunming [8][9][10]. Peat soil is a special soft soil composed of humic groups (HG), soil inorganic matter, and animal and plant residues.…”

Section: Introductionmentioning

confidence: 99%

Effect of UFC on the Microscopic Pore Structure of Cemented Soil in Humic Acid Environment

et al. 2023

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Peat soil is widely distributed in the Dianchi Lake area of Yunnan, and the effect of the cement deep-mixing method on peat soil foundation is mainly affected by humic acid (HA). In this paper, a composite cement curing agent is formed by adding different proportions of ultra-fine cement (UFC) to ordinary Portland cement (OPC) and used to cure the HA-containing cohesive soil. Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and X-ray powder diffraction (XRD) are used to study the influence mechanism of UFC on the micropore structure of HA-containing cemented soil. The unconfined compressive strength test (UCS) is used to verify it. MIP, SEM, and XRD results show that UFC can significantly improve the microscopic pore structure of the samples. The hydration reaction rate of cement increases with the increase in the proportion of UFC, and the generated hydration products can fill the pores of the samples. The filling effect of hydration products on macropores is enhanced, and the pores change from fibrous filling to cemented filling. The enhanced cementation of the hydration products improved the loose and overhead structure inside the sample. Enhancing the cementation of hydration products improves the loose and overhead structure inside the sample and the integrity of cemented soil. UCS verified that the increase in the UFC proportion increases the HA-containing cemented soil strength. It achieves the purpose of reducing the amount of cement when curing peat soil foundations and supports reducing carbon emissions in practical projects.

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“…For example, in 2003, the complexation of uranium by humic acids and fulvic acids was studied to obtain information on uranium binding onto functional groups of humic substances [15]. In 2015, Cao Jing et al [16] provided particular theoretical support for exploring the effect of cement-strengthening peat soil foundations around Dianchi Lake. They guided the actual project surrounding Dianchi Lake.…”

Section: Introductionmentioning

confidence: 99%

“…It can be observed that the erosion of the peat soil environment on the sample is from top to bottom. On the other hand, adding humic acid enhances the dispersion of clay particles on the surface, deteriorating cement soil samples' physical properties and structure [16]. The rate of contact and rotation between fulvic acid solution and cement hydration products increases, and the erosion rate is correspondingly faster.…”

mentioning

confidence: 99%

Study on the Corrosion Behavior of Cemented Organic Soil in Dianchi Lake, China

Liu,

Cao,

Song

et al. 2023

Materials

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To study the corrosion behavior of cement soil in peat soil, the experiment involves the preparation of peat soil by incorporating humic acid into cohesive soil with a lower organic matter content. Cement soil samples are then prepared by adding cement to the mixture. These samples are subjected to immersion in fulvic acid solution and deionized water to simulate different working environments of cement soil. The experiment considers immersion time as the variable factor. It conducts observations of apparent phenomena, ion leaching tests, and unconfined compression strength tests on the cement soil. The experiment results are as follows: (1) With increasing immersion time, the surface of the cement soil in the peat soil environment experiences the disappearance of Ca(OH)2 and calcium aluminate hydrate. Additionally, large amounts of bird dropping crystals precipitate on the surface and within the specimen. The cement soil undergoes localized disintegration due to extensive erosion caused by swelling forces. (2) In the peat soil environment, fulvic acid reacts with the hydration products of cement, resulting in partial leaching of ions such as Ca2+, Mg2+, Al3+, and Fe3+ into the immersion solution. The lower the pH of the fulvic acid immersion (indicating higher concentration), the more significant the ion leaching. Increasing the ratio of humic acid to cement can slow down the leaching of ions. The cement soil undergoes dissolutive erosion in the peat soil environment. (3) The peat soil environment exerts both strengthening and corrosive effects on the cement soil. Cement soil without humic acid exhibits noticeable corrosion in the peat soil environment, gradually decreasing strength as immersion time increases. The strength decreases by 83% from 28 to 365 days. In contrast, cement soil with humic acid experiences an initial period of strengthening, leading to a significant increase in strength in the short term (34% increase from 28 to 90 days). However, the corrosive effects gradually dominate, resulting in a decrease in strength over time. The strength decreases by 80% from 90 to 365 days. This study also explores the strengthening effects of peat soil on cement soil. It identifies phenomena such as extensive erosion and new substance precipitation in cement soil.

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Study on Strength Development and Microstructure of Cement-Solidified Peat Soil Containing Humic Acid of Dianchi Lake

Cited by 8 publications

References 12 publications

Dry-wet cycles durability of solid waste based cementing materials solidifying different characteristic soils

Dry-wet cycles durability of solid waste based cementing materials solidifying different characteristic soils

Effect of UFC on the Microscopic Pore Structure of Cemented Soil in Humic Acid Environment

Study on the Corrosion Behavior of Cemented Organic Soil in Dianchi Lake, China

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