Water sludge reuse as a geotechnical component in road construction: Experimental study

Fiore, Fabiana Alves; Rodgher, Suzelei; Koga-Ito, Cristiane Yumi; Bardini, Vivian Silveira dos Santos; Klinsky, Luis Miguel Gutiérrez

doi:10.1016/j.clet.2022.100512

Cited by 9 publications

(8 citation statements)

References 32 publications

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“…Both materials were classified as silty sands. The granulometric distribution of WTS exhibited similarities to the aluminum WTS examined by Fiore et al [4]. This similarity can be attributed to both WTSs undergoing thermal pre-treatment ranging between 150 and 180 °C.…”

Section: Geotechnical Characterization Of Soil and Wtpssupporting

confidence: 66%

“…The highest incorporation percentages were reported by Fiore et al [4], who used post-thermal-treated WTS without stabilizers, with their evaluation confined to clayey sand and clayey soil. This highlights the need for new assessments of WTS utilization under similar conditions across different soil types and with the inclusion of stabilizers.…”

Section: Introductionmentioning

confidence: 91%

“…This enabled determination of the optimal moisture content (OMC) and maximum dry unit weight (DUWmax) for each sample. In constructing all pavement layers, the compaction operation aimed to achieve maximum stability and reduce settlement due to traffic [4]. To evaluate the strength of the materials, California bearing ratio (CBR) tests were carried out in accordance with the NBR 9895 standard [59].…”

Section: Mechanical Viability Analysis Of Mixturesmentioning

confidence: 99%

“…The treatment of raw water produces residual by-products during the decantation and filtration stages, known as water treatment sludge (WTS). This residue contains impurities removed from the raw water, along with chemicals used in the water treatment processes [3], and polymers utilized in dewatering [4]. Undried WTS consists of over 97% water and primarily includes soil particles (sand, silt, and clay), organic material, nutrients, algae, bacteria, and viruses [5].…”

Section: Introductionmentioning

confidence: 99%

“…Iron-and aluminum-based salts, which are normally used as coagulants for water purification because they help in the effective precipitation of water impurities, are colored inorganic elements of the outflowing WTS. Therefore, in general, these residues are called iron sludge and aluminum sludge [4].…”

Section: Introductionmentioning

confidence: 99%

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Beneficial Use of Water Treatment Sludge with Stabilizers for Application in Road Pavements

Takao,

Bardini,

de Jesus

et al. 2024

Sustainability

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Water treatment sludge (WTS) is the residue produced during water treatment processes for public use. Exploring the reintroduction of these wastes into the production chain to generate new, value-added materials presents a current challenge. This could promote their reuse and reduce the negative environmental impacts associated with their disposal. This study assessed the technical feasibility of using aluminum-based WTS to partially replace silty sand soil in mixtures that include two stabilizers (hydrated lime and Portland cement), potentially for use in road pavements. After conducting a thorough physical, chemical, and geotechnical characterization of both the soil and the sludge, bench-scale experiments were carried out to test the mixtures’ resistance, with WTS proportions of 5%, 8%, 10%, 15%, and 20%, stabilized with either lime or cement. The findings confirm that WTS does not contain potentially toxic elements, according to Brazilian standards, and all tested composites appear suitable for paving. However, the mechanical resistance of the soil–sludge–cement mixtures decreases as the WTS content increases, with an optimum California bearing ratio (CBR) of 41.50% achieved at a 5% WTS addition. Meanwhile, incorporating 15% WTS into soil–sludge–lime mixtures resulted in the highest CBR value of 21.25% for this type of mixture. It is concluded that incorporating stabilizers into soil–WTPS mixtures for road construction allows for an increased percentage of WTPS in silty-sandy soils. Further studies are recommended with different soil types and the addition of fibers to the mixes, to assess the long-term performance of the structure, along with economic and environmental analyses.

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Section: Geotechnical Characterization Of Soil and Wtpssupporting

confidence: 66%

Section: Introductionmentioning

confidence: 91%

Section: Mechanical Viability Analysis Of Mixturesmentioning

confidence: 99%