Experimental Study of Moisture Content Effect on Geotechnical Properties of Solidified Municipal Sludge

Chen, Yijun; He, Xingxing; Wang, Ping; Wan, Yong; Tan, Xiaodong

doi:10.1155/2020/8794076

Cited by 3 publications

(8 citation statements)

References 21 publications

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“…The main ingredient used for hydration-based hardening is OPC (e.g., [8][9][10][11]13,14,[22][23][24]), which undergoes hydration-hardening to produce calcium silicate hydrate and calcium aluminate hydrate. Moreover, [11] used sulphoaluminate cement, which also undergoes hydration reaction to produce similar hydration products (e.g., [25]). In some studies, quicklime (CaO) and gypsum were also used (e.g., [11,12,22,24]).…”

Section: Authors Sludge Type Binder(s) Resultsmentioning

confidence: 99%

“…Moreover, [11] used sulphoaluminate cement, which also undergoes hydration reaction to produce similar hydration products (e.g., [25]). In some studies, quicklime (CaO) and gypsum were also used (e.g., [11,12,22,24]). However, while quicklime hydrates under water, the reaction does not result in the hardening of admixture.…”

Section: Authors Sludge Type Binder(s) Resultsmentioning

confidence: 99%

“…However, organic matter is commonly present in substantial concentrations. Typical organic content ranges from about 10% to more than 40% (e.g., [11,13,14]). Other constituents which are present in significant concentrations include nitrogen, calcium, phosphorus, silicon, potassium, magnesium (e.g., [15,16]).…”

Section: Composition Of Sewage and Wastewater Sludgementioning

confidence: 99%

“…As Figure 6 shows, the data indicate an inverse relationship between 28-day UCS and void ratio, which is to be expected. However, the data are also dual-banded, with the sandy sewage sludge data and [11] pure sewage sludge data on the left, and the rest of the pure sewage sludge data on the right. Examination of the data shows that the binder-sludge ratio and water content used by [11] are far lower than those used by the other pure sewage sludge studies.…”

Section: Void Ratio As a Possible Characterising Parametermentioning

confidence: 99%

“…Many studies have been conducted on different sewage sludge and soil admixtures with different binders and mix ratios (e.g., [8][9][10][11][12]). However, much of the studies are targeted towards sludge from specific sources and the use of specific new binders.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Strength of Chemically Stabilized Sewage Sludge—Some Inferences from Recent Studies

Lim

Goh

et al. 2021

Geotechnics

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Although there has been a substantial body of research on the chemical stabilization of sewage sludge, most of these results are project-specific and relate mainly to the use of new binders and sewage sludge from specific sources. In this sense, much of the work to date is context-specific. At present, there is still no general framework for estimating the strength of the chemically treated sludge. This paper proposes one such general framework, based on data from some recent studies. An in-depth re-interpretation of the data is first conducted, leading to the observation that sludge, which has coarse, hard particulate inclusions, such as sand, premixed into it, gives significantly higher strength. This was attributed to the hard coarse particles that lower the void ratio of treated soil, are much less susceptible to volume collapse under pressure, and contribute to the strength through frictional contacts and interlocking. This motivates the postulation of a general framework, based on the premise that coarse, hard particulate inclusions in the sludge which do not react with the binders can nonetheless contribute to the strength of the treated soil. The overall void ratio, defined as the volume of voids in the cementitious matrix normalised by the overall volume, is proposed as a parameter for quantifying the combined effect of the coarse particulate inclusions and the cementitious matrix. The binder-sludge ratio is another parameter which quantifies the strength of the cementitious matrix, excluding the hard particulate inclusions. Back-analysis of the data suggests that the significance of the binder-sludge ratio may diminish as the content of hard particulate inclusions increases.

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Section: Authors Sludge Type Binder(s) Resultsmentioning

confidence: 99%

Section: Authors Sludge Type Binder(s) Resultsmentioning

confidence: 99%

Section: Composition Of Sewage and Wastewater Sludgementioning

confidence: 99%

Section: Void Ratio As a Possible Characterising Parametermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Strength of Chemically Stabilized Sewage Sludge—Some Inferences from Recent Studies

Lim

Goh

et al. 2021

Geotechnics

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Fluidized solidified soil using construction slurry improved by fly ash and slag: preparation, mechanical property, and microstructure

Feng,

Lin,

Zhang

et al. 2024

Mater. Res. Express

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Fluidized solidified soil (FSS) is a cement-based engineering matergood working performance and mechanical properties. Based on fixed cement and desulphurisation gypsum (DG), fly ash (FA) and ground granulated blast furnace slag (GGBS) were added as admixtures to the construction slurry to prepare three types of FSS: namely cement-GGBS-DG FSS (CGD-FSS), cement-FA-GGBS-DG FSS (CFGD-FSS), and cement-FA-DG FSS (CFD-FSS). Considering 7 d, 14 d, and 28 d three curing times, compressive, flexural, scanning electron microscopy (SEM), and X-Ray diffraction (XRD) analyses were conducted to explore the time-dependent mechanical properties and microscopic characterisation of FSS. The mechanical test showed that CFGD-FSS doped with FA and GGBS had better fluidity, compressive strength, and flexural strength than CGD-FSS doped with FA alone and CFD-FSS doped with GGBS. The CFGD-FSS specimen with a cement:FA:GGBS:DG ratio of 30: 10: 40: 20 in the curing agent had the best mechanical properties, i.e., the CFGD01 specimens. It has fluidity of 189 mm, compressive strength of 671 kPa, and flexural strength of 221 kPa with a 28d curing time, which can meet the working requirements of FSS for filling narrow engineering spaces. And compared with other specimens, it has the shortest setting time, which can effectively shorten the construction period. Microscopic analysis showed that a large number of hydration products, such as calcium silicate hydrate, calcium aluminate hydrate, and ettringite (Aft), were well-formed in the FSS, resulting in good mechanical properties, especially for the CFGD-01 specimens. Finally, two empirical models were established to describe the compressive strength–porosity and flexural strength–porosity relationships. Moreover, the investigated data agreed well with the modelling results.

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Numerical Simulation of Vacuum Preloading for Chemically Conditioned Municipal Sludge

Li¹,

Zhan²,

Wang³

et al. 2023

Journal of Renewable Materials

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Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants. Among recent studies, pilot and field tests showed that chemical conditioning combined with vacuum preloading can effectively treat municipal sludge. To further understand the drainage and consolidation characteristics of the conditioning sludge during vacuum preloading, a large deformation nonlinear numerical simulation model based on the equal strain condition was developed to simulate and analyze the pilot and field tests, whereas the simulation results were not satisfactory. The results of the numerical analysis of the pilot test showed that the predicted consolidation degree was greater than that measured by the field tests, which is attributed to the relatively low permeability layer formed during the preloading process of the prefabricated vertical drain. To better reflect the consolidation process of the conditioned sludge, a simplified analysis method considering the low permeability layer around the prefabricated vertical drain was proposed. The initial permeability coefficient of the low permeability layer is determined via numerical simulations using finite difference method. The predicted settlement curve was in good agreement with the measured results, which indicated that the numerical simulation based on the equal strain condition considering the relatively low permeability layer can better analyze the consolidation process of ferric chloride-conditioning sludge with vacuum preloading.

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Experimental Study of Moisture Content Effect on Geotechnical Properties of Solidified Municipal Sludge

Cited by 3 publications

References 21 publications

Strength of Chemically Stabilized Sewage Sludge—Some Inferences from Recent Studies

Strength of Chemically Stabilized Sewage Sludge—Some Inferences from Recent Studies

Fluidized solidified soil using construction slurry improved by fly ash and slag: preparation, mechanical property, and microstructure

Numerical Simulation of Vacuum Preloading for Chemically Conditioned Municipal Sludge

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