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Lightweight Alkali-Activated Material from Mining and Glass Waste by Chemical a...
Kastiukas, Gediminas; Zhou, Xiangming; Wan, Kai Tai; Gomes, João CastroA foamed alkali-activated material (FAAM) based on tungsten mining waste (TMW) and municipal waste glass (WG) is fabricated by using aluminum powder and organic surfactant foaming agents. The compressive strength and density of the FAAM are in- vestigated in terms of different parameters of production and formulation, including curing temperature as well as the dosage of Na2O, foaming agent, foam catalyzing age...
Agregados leves impregnados por imersão com materiais de mudança de fase e sela...
Gomes, João Castro; Kheradmand, Mohammad; Zoorob, Salah; Silva, Pedro Dinho da; Azenha, Miguel; Aguiar, JoséA presente invenção está relacionada com a obtenção e método de preparação de agregados leves, impregnados com materiais de mudança de fase e impermeabilizados superficialmente. a presente invenção aplica-se, por exemplo, em misturas para pavimentos de modo a permitir atrasar o processo deformação de gelo na sua superfície. esta invenção abrange diferentes agregados leves e apresenta um método de impregnação po...
Alkali-activation of tungsten mining waste mud blended with waste glass: reacti...
Gomes, João Castro; Magrinho, Manuel; Sedira, Naim; Beghoura, Imed; Humbert, Pedro; Manso, Maria; Fernandes, Ana; Silva, RafaelMines and quarries waste accounts for about 29% of the total generated waste from industrial processes and households in Europe. The reuse of mud tailings as precursor materials for alkali-activated binders and applications are very promising from a technical and environmental point of view. The aim of the present study was to develop added-value solutions to reutilize tungsten mine mud tailings in alkali activ...
Smart Textiles for Strengthening of Structures
Górski, Marcin; Krzywoń, Rafał; Dawczyński, Szymon; Szojda, Leszek; Salvado, Rita; Lopes, Catarina; Araújo, Pedro; Velez, Fernando J.This paper presents results of mechanical tests on a prototype of an innovative structural strengthening in form of self-monitoring fabric. Smart textile employs carbon fibers conductivity for measuring strains while monitoring changes of electric resistance under increasing load. A general solution was tested in a series of calibrating tests on strengthening of small size concrete slabs. Promising results of s...
Development and optimisation of phase change material-impregnated lightweight a...
Kastiukas, Gediminas; Zhou, Xiangming; Gomes, João CastroMacro-encapsulated aggregates (ME-LWAs) consisting of expanded clay lightweight aggregates (LWAs) impregnated with a paraffin wax phase change material (PCM) was produced. To fully exploit the thermal energy retaining properties of PCM, it is fundamental to retain as much of the PCM as possible within the pores of the LWA. This paper investigates 3 different commercial materials to create a total of 14 differen...
Chloride penetration into carbonated concrete
Malheiro, Raphaele Lira Meireles Castro; Camões, Aires; Meira, Gibson; Amorim, M. T. Pessoa de; Gomes, João Castro; Reis, RuiTo ensure the durability of concrete structures it is necessary to understand its behaviour in the presence of aggressive agents. Carbonation and chloride action are the two leading causes of degradation in reinforced concrete structures. Â Despite the combined action of these two mechanisms being a reality, there is little research on the effect of CO2 presence on the chloride behaviour in concrete. This work ...
Permeability properties of self-compacting concrete with coarse recycled aggreg...
Oliveira, Luiz Antonio Pereira de; Nepomuceno, Miguel; Gomes, João Castro; Vila, Maria de Fátima CarmoThis article addresses to the issue of durability related properties of self-compacting concrete (SCC) with the use of coarse recycled aggregates obtained from demolition of concrete structures. The objective was to verify the influence of recycled aggregates on SCC permeability properties. For this purpose four different types of concrete mixes were produced, one of them used as reference with natural coarse a...
The influence of wastes materials on the rheology of rendering mortars
Oliveira, Luiz Antonio Pereira de; Gomes, João Castro; Nepomuceno, MiguelThe objective of this paper is to present the results of a research about the effect of mineral additions and some lightweight aggregates from wastes materials (crushed EPS and Cork) on the rheological properties of renderings mortars. Four series of mortar formulations were prepared. Each series was composed by four mortars mixes with different mineral additions: hydrated lime (L), glass powder (G), tungsten a...
Reciclagem de agregados das minas da Panasqueira como revestimento refratário d...
Herrera, J. Montoya; Suarez, J.A. Durán; Silva, Abílio P.; Cano, R. Peralbo; Gomes, João CastroNas minas da Panasqueira (Covilhã, Portugal) acumulam-se montes de resíduos (agregados) provenientes da extração de tungsténio sem qualquer aplicação. Este trabalho pretende contribuir para implementar um novo uso para estes resíduos integrando-os como revestimento refratário no processo de moldação a verde da fundição de metais não ferrosos. Os resultados mostram o potencial do uso destes resíduos da fundição ...
Effect of acrylic fibres geometry on physical, mechanical and durability proper...
Oliveira, Luiz Antonio Pereira de; Gomes, João Castro; Nepomuceno, MiguelThis paper presents the results of an experimental investigation to verify the feasibility of using acrylic textile fibre to improve cement based mortars properties. The assessment of acrylic fibres influence on mortars properties was performed comparing the physical, mechanical and durability behaviour with mortars produced using glass and polypropylene fibres. The influence of the mixing procedures was also i...