GeoBioSciences GeoTechnologies and GeoEngineering

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Geotechnical Characterization of Biomass Ashes for Soil Reinforcement and Liner Material

Publication . Marchiori, Leonardo; Studart, André; Morais, Maria Vitoria; Albuquerque, Antonio; Andrade Pais, Luís; Boscov, Maria Eugenia Gimenez; Cavaleiro, Victor

Biomass ashes (BA) have been intensively studied as amendments for soil in earthworks. This paper aimed to geotechnically characterize BA from pines and olive trees compared to the soil from Castelo Branco, Portugal. Namely, granulometry, specific gravity, Atterberg limits and optimal compaction values were obtained and analyzed in order to valorize the residue incorporated into soils. This work is part of broader efforts to develop an alternative material that can be used in hydraulic barriers as liners and for soil reinforcement. Thus, BA can contribute to reductions in weight and plasticity, and filling properties. Further studies are needed, particularly mechanical and hydraulic performance tests.

2022-08-10Journal article

Open access

Analysis of the chemical properties of almond and walnut shells for use in earthworks

Publication . Nouioua, Thamer; Marchiori, Leonardo; Albuquerque, Antonio; Silva, Flora Cristina Meireles; Pais, Luís Andrade; Cavaleiro, Victor

Almond (AS) and walnut shells (WS) have attracted the interest of scientific community due to the possibility of developing innovative eco-friendly materials. This work aims to analyze the chemical characteristics of AS, WS, a residual granitic soil (RGS) and two mix-tures of waste:soil (10:90% and 40:60%) for evaluating their compatibility for earthworks application. Results show that both wastes could be incorporated into RGS for improving its properties and additionally can remove some water pollutants due to the presence of K2O, CaO and SiO2. This application could reduce the need to use soil natural resources, incineration of both wastes or their deposition in sanitary landfills and can promote their valorization and even create value-added products in the scope of the circular economy. However, additional studies are needed for a better understanding of their potential for using in earthworks, namely leaching, solubilization and adsorption experiments.

2023-09Book part

Open access

Mechanical and Chemical Behaviour of Water Treatment Sludge and Soft Soil Mixtures for Liner Production

Publication . Marchiori, Leonardo; Studart, André; Albuquerque, Antonio; Andrade Pais, Luís; Boscov, Maria Eugenia Gimenez; Cavaleiro, Victor

Background: Clay-based and geosynthetic liners are generally used as hydraulic barriers in solid waste disposal facilities, mining tailing ponds, and soil-based wastewater treatment technologies, avoiding the leaching of hazardous compounds into subsoil and groundwater. Water treatment sludge (WTS) is a water treatment plant (WTP) residue which due to hydraulic properties seems to decrease the permeability in WTS:soil mixtures and may become an alternative material to produce sustainable waste-based liners. Objectives: This research aims to characterize and analyse physical, chemical and mechanical parameters of a WTS, a soft soil and four mixtures WTS:soil following 05:95%, 10:90%, 15:85%, 20:80% ratios, Thereby, evaluating the best ratio for producing waste-based liners for civil engineering applications. Methods: The geotechnical characterization was performed for particle size distribution, specific surface, specific gravity, Atterberg limits, and Normal Proctor compaction; chemical composition due to oxides analyses through X-ray fluorescence (XRF), mineralogical description by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) coupled for imaging; and mechanical behavior performing - –oedometric consolidation, consolidated undrained (CU) triaxial, and falling head permeability. Tests were conducted for all mixtures, the soil, and WTS, with pointed-out exceptions. Results and Discussion: The results showed that the fine-grained WTS filled the soil voids but rearranged soil particles, thus, compacted dry unit weight decreased with WTS addition, probably due to its chemical composition with high amounts of aluminium and silica. The compressibility of the compacted mixtures did not differ significantly compared to the soil, while the shear strength analysis demonstrated a reduction in cohesion and an increase in the effective internal friction angle proportional to WTS addition. Hydraulic conductivity increased with WTS until 10% of residue introduction, decreased for 15%, and continued to decrease for 20%, reaching optimum permeability at 15%. Conclusion: The incorporation of WTS can improve or just not interfere with soil’s properties to be used as liner material in solid wastes storage facilities, mining ponds and soil-based wastewater treatment technologies. Furthermore, 15% of WTS (15:85% mixture) incorporation provided the best results meeting the hydraulic conductivity requirement for liner materials, i.e., equal, or lower than 10-9 m/s. The reuse of WTS for this purpose would allow producing a new added-value material in the scope of circular economy.

2022-12-26Journal article

Open access

New Methodology for Rocks’ Geomechanical Characterization with Schmidt Sclerometer

Publication . Cavaleiro, Victor; Marchiori, Leonardo; Morais, Maria Vitoria; Marchi Oliveira, Gabriel; Cocchiarale, Marcela

Hardness is a parameter that gives information about the behavior of rocks when subjected to certain deformations. Various non-destructive tests are available for hardness quantification, the use of the Schmidt Sclerometer is the most used due its expedition, among existing sclerometers, the Schmidt rebound hammer, type N-34, with an impact energy equal to 2,207 N.m (0.225 Kgm) was selected for experimental tests. Schmidt's hardness index (R) obtained were related to other physical parameters of the rock, namely uniaxial compressive strength (UCS), elasticity modulus (Ɛ), specific gravity and granularity. For comparison purpose, several literature’s methodologies are present focused on improving procedures and developing correlations for different rock types. In this sense, to assess the methodology that best suits granitic rocks’ characterization, several laboratorial and “in situ” tests from the literature were performed. Additionally, the paper proposes a new methodology based on the analysis of the results and a good relation between R and UCS parameters, concluding reliability on the methodology for values of non-porphyroid granitic rocks, predominantly biotitic and from medium to fine granularity, in a precise and consistent way.

2023-06-06Book part

Open access

Valorização de cinzas de biomassa vegetal para aplicações geotécnicas

Publication . Marchiori, Leonardo; Studart, André; Morais, Maria Vitoria; Albuquerque, Antonio; Andrade Pais, Luís; Boscov, Maria Eugenia Gimenez; Cavaleiro, Victor

As cinzas de biomassa vegetal (CBV) têm sido intensamente estudadas para incorporação em solos em obras de terra. Este trabalho tem como objetivo caracterizar química e geotecnicamente cinzas de pinheiros e oliveiras em comparação com um solo de Castelo Branco (Portugal), com a finalidade de aplicações geotécnica. Avaliações físicas, mineralógicas e químicas são necessárias para investigar a origem dos materiais, nomeadamente para determinar se as CBV têm contaminantes, como metais pesados, em sua composição e suas características físicoquímicas. Considerando que há elevadas quantidades de CBV produzidas pelo mundo e um consequente excesso de deposição em aterros sanitários ou queima, a investigação por novas soluções para a sua reutilização é cada vez mais necessária tendo em atenção quesitos atuais de desenvolvimento sustentável, redução do impacto ambiental e economia circula. A engenharia civil, nomeadamente nas áreas da construção, vias, saneamento e geotecnia, oferece várias oportunidades para investigação da aplicação destes resíduos. Neste âmbito, o reforço de solos e a aplicação de liners se destacam, pois podem beneficiar das caraterísticas físico-químicas e mecânicas das CBV para melhorarem parâmetros como a resistência mecânica e permeabilidade. Foram realizados ensaios de caracterização para as CBV e para um solo fraco, nomeadamente distribuição granulometrica, densidade específica dos grãos, limites de Atterberg, composição química por fluorescência de raio-x e mineralogia por difração de raio-x. Este trabalho faz parte de uma investigação mais ampla para desenvolver um material alternativo que possa ser utilizado em obras de terra de revestimento e reforço de solos. Os resultados demonstram que a introdução das CBV em solos pode contribuir para reduzir o peso específico e a plasticidade e melhorar as propriedades mecânicas do material, consequência também do enriquecimento de minerais pozolânicos devido à sua composição química. Desta forma, as CBV deram boas indicações para serem introduzidas em solos em diferentes percentuais, para melhorar as suas propriedades ou para a produção de liners, sendo necessário realizar futuros testes acerca do desempenho mecânico e ensaios de compressibilidade edométrica e compressão triaxial, condutividade hidráulica e potencial de lixiviação de poluentes, de modo a avaliar a sua sustentabilidade e durabilidade e afastar eventuais impactos no ambiente e saúde pública.

2023-08Book part

Open access