Fiber Materials and Environmental Technologies

Funder

Organizational Unit

Publications

Mechanical and hydraulic long-term behavior for an experimental compacted liner embankment

Publication . Marchiori, Leonardo Perelló; Cavaleiro, Victor Manuel Pissarra

Mechanical and hydraulic performance, as compaction, consolidation, and permeability, play an important role in the design and construction of earthworks. A bad dimensioning of this magnitude can lead to major disasters, making structures unfeasible, losing resources and even lives. This work looks to correlate quick tests of soil mechanics with parameters that are difficult to obtain - in situ and laboratory tests -, either because of lack of resources or the access in some unexplored areas. An experimental embankment located in Penalobo, Guarda (Portugal) was chosen to perform in situ tests and sampling for laboratorial tests. The tests for geotechnical characterization – specific gravity, Atterberg limits, particle size distribution, Normal Proctor compaction, soil density gauge, and gamma densimeter -, mechanical behavior – free expansibility, one-dimensional oedometric consolidation, consolidated undrained triaxial shearing, plate load test, dynamic penetration lightweight, and heavyweight, and cone penetration test -, chemical composition – x-ray diffractures, fluorescence, scanning energy microscopic images, cation exchange capacity, and pH -, and hydraulic conductivity through falling head permeameter permitted to correlate several parameters. Results characterize the soil as a typical granitic soil, a well-graded sand without plasticity classified as A-1-b according to AASHTO, specific gravity of 2.55, with optimal compaction following w = 14.0% and ?d = 1.86 g/cm3 . Mainly composed by quartz, kaolinite, and muscovite, along with high amounts of SiO2 and Al2O3, besides lower percentages of NaO2 and Fe2O3, also showed pH = 6.0 and cation exchange capacity = 17.0 meq/100g. The soil has high free expansibility, although low oedometric compressibility when compacted, effective internal friction angle is around 35º and has no cohesion. Several rounds of tests were made for this evaluation, and since the site is studied for over ten years, another analysis on behalf of long-term behavior of the structure was carried out. Long-term behavior analysis and parameters correlations were developed around compaction characteristics within Normal Proctor, soil density gauge and gammadensimeter results; direct and indirect hydraulic conductivity through oedometer and permeameter laboratorial tests; drilling tests relationship among dynamic penetration lightweight, and heavyweight, standard penetration test, and cone penetration tests; in addition to laboratorial oedometer and in-situ plate load test analysis the consolidation of the embankment liner.

2022-12-13Master thesis

Open access

Design and Engineering of Tissue Papers using Cellulose-based Fibrous Materials 3D Simulations: an approach for Furnish Optimization

Publication . Morais, Flávia Pinto; Curto, Joana Maria Rodrigues; Amaral, Maria Emília da Costa Cabral; Carta, Ana Margarida Martins Salgueiro

In recent years, the tissue paper industry has been exposed to several challenges related to the growing relevance and demand for raw materials (furnish) and sustainable products. Cellulose fibers are excellent raw materials, due to their intrinsic characteristics, leading to their use in various products, such as tissue papers. These materials serve multiple purposes, combining cost-effectiveness with increasingly demanding hygiene criteria. The knowledge of the different types of pulp fibers and the results of their modifications by engineering processes contributes to the design of tissue paper materials with the best combination of furnish, for the several types of final products. This work explores the furnish optimization of tissue products, through the development and application of advanced computational tools. A methodology that combines experimental and computational planning was implemented to establish relationships between the key fiber and structure properties, the process steps that modify them, and the structural and functional tissue paper properties. This led to the development of a simulator for furnish optimization and management, the SimTissue. This work presents a significant and innovative contribution in the 3D fiber characterization and modeling, in the application of experimental and computational approaches to evaluate the engineering of fiber and structure modification processes, and in the optimization using advanced computational tools to design soft, resistant, and absorbent tissue materials. The characterization of the fiber dimensions in the paper structure, in the three dimensions (3D), was fundamental to model them, using SEM images methodologies and advanced computational tools for fiber and structure modeling. As a result of this strategy, 3D fiber models were developed, implemented, and used as input variables in computational simulations to predict the structural properties. A representative set of cellulose pulps of industrial interest were selected and characterized, obtained from hardwood and softwood species with different cooking and bleaching processes. The contribution of these pulp fibers with different morphological, chemical and water interaction properties to the tissue properties was accessed through several correlations. Therefore, a planning was implemented from the point of view of engineering fiber and structure modification process variables, influencing the design of tissue paper materials. The pulps were subjected to enzymatic and mechanical treatment, and incorporation of additives in suspension, including micro/nanofibrillated cellulose (MFC/NFC) and biopolymers. All these sets of trials were investigated to quantify their influence, singular or in combination, on the key tissue properties: softness, strength, and absorption. A production methodology of laboratory-made isotropic structures of 20 g/m2 instead of 60 g/m2, with pressing step suppression, was proposed following an adaptation of ISO 5269-1, in order to mimic tissue papers and evaluate these tissue properties. The establishment of relationships between these pulp fibers, the multiple changes resulting from the different processes, and the functional tissue properties was obtained using several computational tools, such as decision/regression trees, multiple linear regressions, artificial neural networks, among others, used as models to support planning and decision-making in industrial production. Therefore, the validation of computational models with these structures was an innovative and irreplaceable milestone to obtain a 3D computational simulator with predictive capacity for tissue structures. This entire process allowed the computational implementation of the SimTissue through the programming of algorithms for the calculation engine and database integration, to be used in specific cases to support industrial furnish management. The design of tissue fibrous materials using these computational tools allowed the development of furnish combinations and process parameters that led to the optimization of each tissue paper. This assisted in the decision of which pulps were most suitable for a given product and which enzymatic and mechanical treatments or additives incorporation enabled an optimized tissue material. By applying this methodology, it was possible to produce tissue structures with maximization of eucalyptus fibers, minimizing the incorporation of softwood pulp fibers, and quantifying the implications of the choices on the final end-use tissue properties. Hence, SimTissue predicts the influence of various types of raw materials used in formulations to produce tissue materials, the influence of modification processes, and the incorporation of additives. The validation of the properties’ prediction was performed with experimental and simulated structures. Each simulation performed can also be compared with formulations with 100% eucalyptus fiber pulps, or with different percentages of other hardwood and softwood fiber pulps, which reflects the ratio used by the tissue paper industry. The present work describes an experimental and computational approach, with the design and development of a predictive capacity tool, with the integration of fundamental variables, to optimize innovative furnish formulations, saving laboratory and industrial resources. This multiscale system, with multiple inputs and multiple outputs, was integrated using computational tools, modeling, and optimization methods. The development of the SimTissue was an innovative milestone to obtain the predictive capability of tissue structures, to support industrial production in furnish management and optimization. The materials design strategy using this computational tool can also be applied to the development of value-added fibrous materials based on eucalyptus fiber and including additives and fibers with micro and nanoscale.

2022-11-22Doctoral thesis

Open access

Evaluation of the potential use of water treatment sludge (WTS) as a waterproofing material for waste containment earthworks

Publication . Marchiori, Leonardo; Studart, André; Morais, Maria Vitoria; Albuquerque, António; Cavaleiro, Victor

Industrial wastes’ incorrect disposal can cause groundwater and soils contamination. In this aspect, the water treatment sludge (WTS) appears as a potential residue to be valorized within soils in order to enhance wastes’ stabilization while mitigating its environmental impacts. Therefore, geotechnical and chemical evaluations were conducted for assessing WTS’s potential as a waterproofing agent for earth works, considering their impacts on the properties of the analyzed clayey soil for assessing possible soil’ reinforcement through a further investigation. Found results on the WTS characterization have shown a high percentage of fines, which contributes for the reduction of the soil’s plasticity. In addition, its chemical composition is compatible with pozzolanic characteristics while being possible to associate the analyzed WTS with materials already used in earth works. These results indicate a solid beginning for a complete characterization of the WTS and its stabilization within soils as they indicate possible reinforcement of clayey soils and use for liners application, which have yet to be confirmed by in-depth investigations around resistance and permeability properties.

2021-12-20Book part

Open access

Desenvolvimento e otimização de estruturas celulósicas 3D para retenção de moléculas ativas

Publication . Medeiros, João Francisco Bettencourt; Curto, Joana Maria Rodrigues; Silva, Maria Lúcia Almeida da

Nos dias de hoje, o desenvolvimento de sistemas dérmicos baseados em estruturas de base celulósica biodegradáveis constitui um desafio na área da Química Industrial, especialmente pela utilização tanto das fibras de celulose, como de moléculas ativas provenientes de plantas, numa perspetiva de circularidade. Tem-se assistido a um crescente interesse na utilização dos vários tipos de moléculas ativas provenientes da Cannabis sativa L. Neste estudo, estas combinam-se com moléculas ativas de outras plantas, entre as quais a Camellia sinensis L., com o objetivo de desenvolver formulações com interesse comercial. Os compostos ativos e os constituintes voláteis, presentes em ambas as plantas, foram obtidos por hidrodestilação e microextração em fase sólida (HS-SPME), respetivamente, e caracterizados, por cromatografia gasosa acoplada à espectrometria de massas (GCMS). Mais de 60 compostos foram caracterizados no óleo essencial de canábis e mentrastos entre eles o ? cariofileno (14,3%) e o a terpinoleno (10,8%). A análise dos voláteis identificou a citronela (10,3%) e o ß citronelol (8,9%) como os compostos maioritários presentes. No chá verde da Gorreana, os principais compostos encontrados foram o ácido palmítico e (25,5%) e a cafeína (12,8%). Neste trabalho foram caracterizados diferentes materiais de base celulósica, de hardwood e softwood, modificando a sua estrutura por métodos mecânicos, resultando na diminuição da porosidade da matriz produzida de 80% para 50%, e no aumento das propriedades mecânicas, como o módulo de elasticidade, em cerca de 6 vezes, contribuindo para o desenvolvimento de DDS sustentáveis capazes de reter as moléculas em estudo. Otimizaram-se os métodos de extração das fibras de Cannabis sativa L. a partir de caules cortados e submetidos ao cozimento alcalino com NaOH a 140ºC, obtendo-se características estruturais de acordo com os requisitos para as aplicações pretendidas. A incorporação das fibras de cânhamo às fibras de papel industrial tissue resultaram no aumento do índice de tração em mais de 60% e do módulo de elasticidade da estrutura de 1650 MPa para 2318 MPa. O desenvolvimento e otimização de estruturas 3D permitiu a obtenção de protótipos laboratoriais com potencial para serem utilizados em aplicações dérmicas com maior sustentabilidade ambiental.

2023-07-13Master thesis

Embargoed 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