11 documents found, page 1 of 2
Mitigação das Ilhas de Calor Urbanas através da Incorporação de Fibras Coaxiais...
Araújo, Vitor M. M.; Hammes, Nathalia; Lima Jr., Orlando; Zahabizadeh, Behzad; Cunha, Vítor M. C. F.; Pereira, Eduardo; Camões, Aires[Excerto] Introdução: As Ilhas de Calor Urbanas (ICU) ocorrem devido à substituição de superfícies naturais por materiais, por exemplo, cimentícios e asfálticos, que apresentam elevado calor específico e tendem a reter calor por longos períodos. Uma estratégia promissora para mitigar este efeito pode ser a utilização de argamassas com microfibras contendo materiais de mudança de fase (PCMs). Esses materiais aju...
Infrared thermography of cement mortar with phase change fibres
Hammes, Nathalia; Araújo, Vitor M. M.; Lima Jr., Orlando; Zahabizadeh, Behzad; Cunha, Vítor M. C. F.; Pereira, Eduardo; Camões, Aires; Marinho, ElinaUrban Heat Islands (UHIs), aggravated by intense urbanisation and heat-retaining materials from buildings and roads, affect the thermal comfort of human beings. To mitigate this issue, this study aims to study the thermal performance of cement mortars with coaxial polymeric fibres produced by wet spinning and containing polyethylene glycol (PEG 600 and 1000) (CM_PCF) as phase change material. Samples were irrad...
Comparative evaluation of photocatalytic efficiency measurement techniques thro...
Lessa, Fabíula Pereira; Lima Jr., Orlando; Margalho, Élida Melo; Zahabizadeh, Behzad; Cunha, Vítor M. C. F.; Pereira, Eduardo; Camões, AiresSelf-cleaning cementitious materials, particularly with TiO2-based photocatalytic coatings, offer significant benefits by reducing surface deterioration and maintenance requirements, even in harsh urban environments. Despite the growing interest in self-cleaning cementitious materials, an international standard test method to calculate their efficiency has not yet been established for this specific type of subs...
Photocatalysis of functionalised 3D printed cementitious materials
Zadeh, Behzad Zahabi; Rocha Segundo, Iran Gomes da; Pereira, João; Freitas, E. F.; Camões, Aires; Teixeira, Vasco M. P.; Costa, Manuel F. M.The main objective of this study was to evaluate the photocatalytic behaviour of 3D printed cementitious mortars that were functionalised with TiO2 nanoparticles. This study is one of the few available regarding functionalisation of 3D concrete printing (3DCP) with photocatalytic properties. Despite the fact 3DCP research is swiftly growing, it is still necessary further investigation to fully understand these ...
Functionalization of smart recycled asphalt mixtures: a sustainability scientif...
Rocha Segundo, Iran; Zahabizadeh, Behzad; Landi Jr., Salmon; Lima Jr., Orlando; Afonso, Cátia; Borinelli, Jaffer; Freitas, E. F.; Cunha, Vítor M. C. F.The sustainable development of our societies demands strong efforts on scientific and technological research while informing and educating students and the general population. Air pollution and road safety hazards constitute two main public health problems that are insufficiently addressed pedagogically. With this work, we aim to contribute to tackeling the problem by presenting the results of scientific resear...
Evaluation of the best solution for the functionalization of photocatalytic, su...
Rocha Segundo, Iran Gomes da; Landi Jr., Salmon; Freitas, E. F.; Costa, Manuel F. M.; Zahabizadeh, Behzad; Cunha, Vítor M. C. F.; Soares, GraçaThis research aims to develop asphalt mixtures with new capabilities with photocatalytic, superhydrophobic, and self-cleaning capabilities. Different solutions were prepared combining nano-TiO2 and micro-PTFE on water, and ethyl alcohol and dimethyl ketone with different concentrations. The solutions were sprayed over the asphalt mixtures and the new capabilities were evaluated via decolourization of Rhodamine ...
Rate effect in inclined fibre pull-out for smooth and hooked-end fibres: a nume...
Poveda, Elisa; Yu, Rena C.; Tarifa, Manuel; Ruiz, Gonzalo; Cunha, Vítor M. C. F.; Barros, Joaquim A. O.Based on a numerical model to simulate the static behaviour of a smooth fibre extracted from a cementitious matrix, a rate dependent friction law, widely used in earthquake engineering for steady-state slip phenomena, is proposed to capture the rate effect observed in dynamic pull-out tests for both smooth and hooked-end fibres. After calibrating the friction coefficients with the experimental results of smooth...
Effect of the displacement rate and inclination angle in steel fiber pullout tests
Tarifa, Manuel; Poveda, Elisa; Cunha, Vítor M. C. F.; Barros, Joaquim A. O.This paper summarizes the results obtained in an experimental campaign on the effect of the displacement pullout rate and the inclination angle of the steel fiber pullout tests. For that purpose, specimens were obtained from a self-compacting concrete with a compressive strength of 86 MPa. In the experimental program, hooked-end steel fibers of 0.75 mm diameter and 60 mm length were used. Tests were executed wi...
Betão de alta resistência reforçado com fibras exposto a elevadas temperaturas
Cunha, Vítor M. C. F.; Al-Rikabi, Taghreed; Barros, Joaquim A. O.Atualmente, a utilização de betões de elevada resistência tem vindo a aumentar, nomeadamente, em aplicações com requisitos especiais, tais como arranha-céus, torres eólicas, centrais nucleares, etc. No entanto, com o aumento significativo da resistência, este tipo de material desenvolve um comportamento significativamente mais frágil. Adicionalmente, quando expostos a elevadas temperaturas, como no caso de incê...
Indirect tensile behaviour of fibre reinforced alkali-activated composites
Almeida, Filipe; Cunha, Vítor M. C. F.; Miranda, Tiago F. S.; Cristelo, NunoThere are currently still some sustainability-related issues that need to be tackled within the construction sector. Namely, cement production is accountable for nearby 5% of the worldwide total CO2-eq release. Therefore, environmentally viable and economically sustainable solutions need to be pursued in order to mitigate the use of Portland cement. The incorporation of industrial waste in concrete compositions...