Characterization of soil- WTP sludge mixtures with the incorporation of strength-enhancing additives for road purposes - hydrated lime and Portland cement

• Grant number: 23/06329-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: January 31, 2024
• Field of knowledge: Engineering - Sanitary Engineering - Basic Sanitation
• Agreement: SABESP
• Principal Investigator: Fabiana Alves Fiore Pinto
• Grantee: Giulianna Luna Bini Carrosa
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Company: Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. Instituto de Ciência e Tecnologia (ICT)
• Associated research grant: 20/12230-4 - Determination of technological requirements for adequation of the physical and chemical properties of water treatment plant sludge, for beneficial use in earth work, AP.PITE

Abstract

The practical, economic, and environmental sense of recycling and reuse of Water Treatment Plant Sludge (WTSL) is related not only to the cost savings of disposal but also to reducing the demand for virgin aggregates, which relieves the environmental burdens associated with mining and quarrying activities. After their dehydration, TLS has characteristics that potentially enable their use in the manufacture of chemically stabilized soils, with additives such as Portland cement and hydrated lime; ceramic materials; pigments for mortars and coatings, or as an additive for aggregates. Hydrated lime is one of the most widely used additives to improve the characteristics of problem soils. The stabilization of soils with hydrated lime is effective in improving the workability of soils and facilitating the construction of subsequent layers; reducing expansive power; improving texture and durability; increasing soil stiffness and consequently improving its resistance to permanent deformation. The use of soil cement in base and sub-base layers, called cemented layers, has been carried out in road sidewalks, urban sidewalks, airports, ports, parking lots, and material storage areas. The addition of cement to soil is a way to improve the plastic qualities of the soil, increasing its strength and reducing its compressibility and permeability. Another advantage of using soil cement on roads is the aspect of environmental protection, with the increasing limitations in exploiting material reserves; in this case, it is possible to incorporate local soils through cement stabilization. Finally, the possibility of reducing the thickness of layers that make up the sidewalk structure, without reducing their structural capacity, is one of the results that can be obtained with the characteristics of soil cement, due to its relatively high modulus of elasticity. It is in this context that this research project is proposed, with the objective of evaluating the use of sludge from water treatment plants (WTP) for the construction of the base and sub-base of road sidewalks.