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

Túlio W. Takao, Vivian S. Bardini, Amanda D. de Jesus, Leonardo Marchiori, Antonio Albuquerque () and Fabiana A. Fiore ()
Additional contact information
Túlio W. Takao: Environmental Engineering Department, Science and Technology Institute, São Paulo State University—UNESP, km 137,9 Presidente Dutra Highway, São José dos Campos 12247-004, SP, Brazil
Vivian S. Bardini: Transportation Engineering Department, School of Technology, Campinas State University (UNICAMP), Limeira 13484-350, SP, Brazil
Amanda D. de Jesus: Environmental Engineering Department, Science and Technology Institute, São Paulo State University—UNESP, km 137,9 Presidente Dutra Highway, São José dos Campos 12247-004, SP, Brazil
Leonardo Marchiori: GeoBioTec, Department of Civil Engineering and Architecture, Universidade da Beira Interior, Fonte Calçada do Lameiro, 6201-001 Covilhã, Portugal
Antonio Albuquerque: GeoBioTec, Department of Civil Engineering and Architecture, Universidade da Beira Interior, Fonte Calçada do Lameiro, 6201-001 Covilhã, Portugal
Fabiana A. Fiore: Environmental Engineering Department, Science and Technology Institute, São Paulo State University—UNESP, km 137,9 Presidente Dutra Highway, São José dos Campos 12247-004, SP, Brazil

Sustainability, 2024, vol. 16, issue 13, 1-13

Abstract: 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.

Keywords: water treatment sludge; cement; lime; stabilizing materials; geotechnical characterization (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2024
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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