Experimental study on solidified dredged sediment with MgO and industrial waste residue

Kong, Xianghui; Zhang, Zhibin; Liang, Yunpeng; Wang, Xiaokang; Liu, Mengmeng

doi:10.1016/j.conbuildmat.2022.130105

Cited by 11 publications

(4 citation statements)

References 46 publications

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“…Cement is widely used for silt solidification; however, significant CO2 emissions are associated with its production, estimated at 1 t CO2/t cement [13,14]. This is not conducive to the realization of China's strategic goal of carbon neutralization [15].…”

Section: Introductionmentioning

confidence: 99%

Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt

Shu,

Zhou,

Gong

et al. 2024

Processes

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In this study, MgO as an environmentally friendly silt-solidifying material was first mixed with silt and then carbonized by injection with CO2. The strength and contaminant leaching characteristics of the MgO-solidified silt were studied using unconfined compressive strength and toxicity leaching tests, and the results were compared with those of cement-solidified silt. The unconfined compressive strength of the silt reached 111 kPa with 9% MgO content and a 14 d curing time. The CO2 injection further increased the unconfined compressive strength of the MgO-solidified silt by approximately 25%: the values for MgO-solidified silts without and with a CO2 injection were approximately 60% and 80%, respectively, of those of the cement-solidified silts with the same additive additions. The leaching concentrations of nutrient salts and heavy metal pollutants in the silt decreased with increased MgO content. Compared with the dredged silt, MgO solidification with carbonization reduced the leaching of total nitrogen and total phosphorus by more than 10% and 50%, respectively: these values were approximately 5% points higher than those of cement-solidified silt. Of the heavy metals, the leaching concentration of Ni was reduced the most. This study provides a theoretical basis and technical support for low-carbon treatment and green resource utilization of dredging silt.

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Section: Introductionmentioning

confidence: 99%

Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt

Shu,

Zhou,

Gong

et al. 2024

Processes

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“…Dredging projects play a crucial role in maintaining river navigation and preventing floods, but they also generate a substantial amount of sediment that poses challenges for proper disposal [1,2]. In China, it has been estimated that the annual production of dredged sediment reaches a staggering 100 million cubic meters [3]. This sediment typically exhibits low strength, high porosity, and high water content, which result in limited direct utilization value [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…In China, it has been estimated that the annual production of dredged sediment reaches a staggering 100 million cubic meters [3]. This sediment typically exhibits low strength, high porosity, and high water content, which result in limited direct utilization value [3,4]. Conventional treatment methods, such as on-site stacking and pit dumping, not only consume vast amounts of land resources but also pose significant environmental pollution risks [5,6].…”

Section: Introductionmentioning

confidence: 99%

Microscopic Mechanism and Road Performance Analysis of MgO Carbonation–Solidification of Dredged Sediment

Kong,

Wang,

Zhang

et al. 2024

Sustainability

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MgO carbonization is a green and low-carbon soil improvement technology. The use of MgO carbonization to solidify dredged sediment and transform it into road-building materials has significant environmental sustainability advantages. A series of microscopic characterization tests, including X-ray Diffraction (XRD), Scanning Electron Microscope–Energy Dispersive Spectrometer (SEM-EDS), and Mercury-in-Pressure (MIP) tests, were conducted to elucidate the evolution characteristics of mineral composition, microscopic morphology, and pore structure of sediment under carbonation. Based on the results, the mechanism of MgO carbonation–solidification of dredged sediment was explored. In order to verify the improvement of carbonation on the road performance of sediment, comparative tests were carried out on sediment, non-carbonated sediment, and carbonated sediment. The results indicate a significant improvement in the solidification of MgO-treated sediment through carbonation, with enhanced macroscopic strength and densified microscopic structure. This can be attributed to the encapsulation, cementation, and pore-filling effects of the hydration products and carbonation products of MgO on soil particles. The rebound modulus and splitting strength of carbonated sediment were 3.53 times and 2.16 times that of non-carbonated sediment, respectively. Additionally, the carbonated sediment showed improved saturated stability, resistance to salt solution wet–dry cycles, and resistance to freeze–thaw cycles.

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“…Rodriguez et al [20] suggest that tropical soils can be stabilized using blends of electric arc furnace slag and fly ash. Kong et al [21] found that 7.62% of reactive MgO, 11.31% of FGD gypsum, and 5.80% of steel slag can make the dredged sediment's microstructure more stable, thus improving its mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a Low-Cement-Content Silty Soil Stabilizer Using Industrial Solid Wastes

Li,

Ma,

Wang

et al. 2023

Applied Sciences

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Silty soil performs poorly when used in roads. Cement is generally used as a stabilizer to treat silty soil and enable it to meet the requirements for roadbed filling. However, cement is an environmentally unfriendly material and can cost much. Meanwhile, solid wastes of ground granulated blast furnace slag (GBFS), fly ash (FA), and flue gas desulfurized (FGD) gypsum are produced in large quantities annually. Therefore, stabilizer A (cement:ground GBFS:fly ash:FGD gypsum = 30:44:15:11) and stabilizer B (cement:ground GBFS:fly ash:FGD gypsum = 40:38:13:9) were investigated in this study by reducing the cement content in the stabilizer and improving the utilization rate of solid wastes. The compressive strength development, California bearing ratio (CBR), temperature shrinkage, mineral composition, and micro-morphology of the stabilized silty soil were measured. The main findings are as follows: firstly, the addition of solid wastes can mitigate the adverse effect of delay time on compressive strength development. Secondly, the proposed stabilizers can significantly improve the CBR, which can reach 60% with a 4% dosage. Additionally, Stabilizer B is believed to improve the resistance to temperature shrinkage, and a higher stabilizer dosage can reduce the rate of decrease in water stability coefficient. Both X-ray diffraction analysis and scanning electron microscope observations show that the main hydration products that contribute to the stabilization are C-S-H and ettringite.

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Experimental study on solidified dredged sediment with MgO and industrial waste residue

Cited by 11 publications

References 46 publications

Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt

Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt

Microscopic Mechanism and Road Performance Analysis of MgO Carbonation–Solidification of Dredged Sediment

Preparation of a Low-Cement-Content Silty Soil Stabilizer Using Industrial Solid Wastes

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