41 documents found, page 1 of 5
Leveraging ML for predicting UCS of soil stabilised with one-part alkali-activa...
Tinoco, Joaquim; Pinheiro, João Manuel Machado; Cristelo, Nuno; Rodrigues, Mafalda; Miranda, Tiago F. S.The transition to sustainable construction materials has driven interest in alternatives to Portland cement. Soil stabilisation with alkali-activated binders is a promising approach, yet its widespread application requires reliable predictive tools for assessing unconfined compressive strength (UCS). This study explores the use of machine learning algorithms to predict UCS in soil stabilised with a one-part alk...
A geotecnia na transição eco-digital das infraestruturas de transporte
Neves, José; Moutinho, João; Freire, Ana Cristina; Paixão, André; Monteiro, Bernardo; Parente, Manuel; Cristelo, Nuno; Correia, A. GomesO artigo apresenta uma compilação de exemplos nacionais de investigação, desenvolvimento e inovação relacionados com a transição verde e a transformação digital no âmbito da geotecnia nos transportes e associados às terraplenagens, pavimentos e vias-férreas. No âmbito da transição verde, são apresentados exemplos de aplicação de materiais não convencionais e renováveis e de técnicas de estabilização baseadas na...
Stabilisation of estuarine sediments with an alkali-activated cement for deep s...
Pinheiro, Claver Giovanni Silveira; Rios, Sara; Fonseca, António Viana da; Cristelo, NunoIn this work, an alternative alkali-activated cement (AAC) made of ladle slag precursor mixed with sodium hydroxide and sodium silicate has been developed to enhance the bearing capacity of estuarine soils in coastal conditions via deep soil mixing (DSM). The AAC was optimized to use a low reactivity precursor (ladle slag) and to deal with a contaminated high-water content natural sediment cured under water. Th...
Application of electric arc furnace slag as an alternative precursor to blast f...
Cristelo, Nuno; Coelho, João Diogo; Rivera, Jhonathan; Garcia-Lodeiro, Inés; Miranda, Tiago F. S.; Fernández-Jiménez, AnaIn steel manufacturing, electric arc furnaces are increasingly common, as they use mostly scrap metal as ore source. Thus, blast furnace slag (BFS) is decreasing, while electric arc slag (EAFS) is proportionally increasing. This study focuses on the potential of EAFS in alkaline cements, as precursor or aggregate. Different EAFS/BFS mixtures, some including fly ash (FA), were activated with a NaOH solution, and...
Sustainability assessment of half-sandwich panels based on alkali-activated cer...
Vaca, Norma Yolanda Gaibor; Mateus, Ricardo; Leitão, Dinis; Cristelo, Nuno; Miranda, Tiago F. S.; Pereira, E. N. B.; Cunha, Vitor M. C. F.This study assessed the sustainability of two partition walls and intended to contribute to the Circular Economy in the construction sector. A life cycle approach and a multi-criteria decision support method were applied to know the environmental, functional, and economic performances of the production process of half-sandwich panels based on alkali-activated ceramic/slag waste cement, choosing as system bounda...
Numerical analysis of a tunnel behaviour considering the spatial variability of...
Miranda, Tiago F. S.; Viana, Ana; Martins, Francisco F.; Guo, Xiangfeng; Cristelo, Nuno; Dias, DanielThis study applies random field theory to simulate the spatial variability of the ground where a tunnel was excavated in a granitic soil mass, in the city of Porto (Portugal). Numerical analyses are performed using finite element method combined with random field theory to simulate tunnel excavation. A parametric study to analyse the influence of the correlation coefficient is performed. The results are compare...
Fiber-reinforced alkali-activated cements from ceramic waste and ladle furnace ...
Gaibor, Norma; Leitão, Dinis; Miranda, Tiago F. S.; Cristelo, Nuno; Fernandes, Lisete; Pereira, E. N. B.; Cunha, Vitor M. C. F.Alkaline-activated cement, as an alternative to conventional portland cement, is being increasingly studied due to its environmental advantages and engineering properties. However, research on the feasibility of using both uncommon precursors and curing at ambient temperature is still limited. This study aims to investigate the potential of ceramic wastes, specifically from brick and tile production and ladle f...
Mechanical behavior of a mine tailing stabilized with a sustainable binder
Manaviparast, Hamid Reza; Pinheiro, João; Najafi, Elmira Khaksar; Abreu, Cláudia; Araújo, Nuno; Cristelo, Nuno; Miranda, TiagoMining is a primary sector for the national economy of many countries, but exploiting these natural resources causes negative impacts on the environment. Tailings produced during mining, called mine tailings, have to be disposed of, and for that purpose, they are often mixed with Portland cement to control environmental toxicity and improve their mechanical properties. However, the high environmental impacts of...
Ophthalmic glass lens waste as an alternative soluble silica source for alkali-...
Khaksar Najafi, Elmira; Tavares, Pedro; Miranda, Tiago F. S.; Reza Manaviparast, Hamid; Cristelo, NunoThis research study was aimed at assessing the potential use of glass powder (GW), from the production of optical lenses, as a substitute of commercial sodium silicate (SS), to produce fly ash-based alkaline cements. The dissolution of the GW and the subsequent activation were achieved either with a cleaning solution (CS) from the aluminium casting industry, and a commercial sodium hydroxide solution (SH) so as...
Characterization of stainless steel spent pickling sludge and prospects for its...
Castro, Fernando; Tavares, Pedro B.; Cristelo, Nuno; Teixeira, Tiago; Garcia, Joana F.; Parreira, Nuno Miguel GermanoFluorspar is considered a critical raw material for the European Union, due to its industrial uses and lack of sufficient extraction in European countries. It is a source for hydrofluoric acid manufacture, this latter chemical being employed, among other uses, in the pickling of stainless steels. From this latter activity, sludge is generated due to the need for used water treatment. In this article, we report ...