Joaquim Antonio dos Reis Silva Simao
@fct.unl.pt
Earth Sciencies Department, NOVA School of Science and Technology (FCT NOVA)
NOVA School of Science and Technology (FCT NOVA)
EDUCATION
2003 - Ph.D. in Geology (speciality Petrology and Geochemistry), Faculdade de Ciências e Tecnologia (UNL).
RESEARCH INTERESTS
• Mineralogy, Petrology, Geochemistry.
•.Experimental alteration of igneous and metamorphic rocks in order to determine their use as natural stone.
• Tests of laboratorial alteration of rocks simulating polluted atmospheres, acid rains, pollutant particles and saline atmospheres.
Scopus Publications
Scopus Publications
Carla Lisci, Carlos Galhano, Joaquim Simão, Vera Pires, Fabio Sitzia, and José Mirão
MDPI AG
Stone deterioration is significantly influenced by the process of salt crystallisation. The expansion of salt crystals on a porous framework exerts pressure on the solid fraction, causing the stone to deteriorate when the internal pressure of salt surpasses the stone’s strength. Protective coatings are employed to effectively hinder or substantially reduce the penetration of water and saline solutions. This study attempts to evaluate the effectiveness and long-term durability of limestones protected with hydrophobic coatings, focusing on their resistance to salt damage. The investigation followed the specifications set by the standard EN 12370:2019 and EN 14147:2003, which assesses the resistance of natural stone to salt crystallisation. The findings of this study indicate the conservation of physical–mechanical properties after ageing tests. In parallel, measurements of the static contact angle and the measurement of quality indexes revealed that the coatings maintained a certain level of hydrophobicity even after undergoing salt weathering tests, maintaining the good quality of the stones.
Fernanda Carvalho, Maria Margarida R．A． Lima, Elissavet Kavoulaki, Nuno Leal, Joaquim Simão, Carlos Galhano, Hugo Águas, Giuseppina Padeletti, and João Pedro Veiga
Elsevier BV
Vera Pires, Luis G. Rosa, Pedro M. Amaral, and Joaquim A. R. Simão
MDPI AG
The evaluation of stone cladding material suitability can be a challenge due to the way that stone physical and mechanical properties, and characteristics such as mineralogy, might influence stone performance as a cladding element in a ventilated facade application. Salts can affect natural stone performance, and one of the experimental methods available to study and predict it is through accelerated aging tests such as salt fog chamber cycles. Aging test results should include the analysis of critical stone physical–mechanical properties to fully understand decay effects. The aim of this study was to reduce the lack of knowledge regarding the implications of salt fog on certain fundamental characteristics of stone cladding requirements, such as elastic properties and flexural strength, because these are particularly important properties for ventilated facade systems. A systematic methodology based on artificial salt fog cycles in a climatic chamber, microscopic analysis, weight measurement, flexural strength, and dynamic elastic modulus was performed on two limestones from Portugal: Moleanos (MO) and Semi-Rijo (SR). This study aims to contribute to improved selection stone methods linked to more sustainable stone facades, and the experimental methodology can be further applied to other stone types, particularly the ones most selected for stone cladding applications near coastal areas. In this work, results of salt fog decay cycles are presented and discussed considering their direct contribution for a better stone-cladding dimensioning process.
H. Ouacha, A. Ben Moussa, J. Simao, Y. El Kharim, and B. Baghdad
Springer Science and Business Media LLC
Sofia Barbosa, António Dias, Diogo Durão, José Grilo, Gonçalo Baptista, Jonhsman Cagiza, Sofia Pessanha, Joaquim Simão, and José Almeida
MDPI AG
In this case study, 2D micro energy dispersive X-ray fluorescence (µ-EDXRF) surveys were performed in the nepheline syenite (NS) of “Serra de Monchique” located in the southwest region of Portugal (Algarve, Iberian Peninsula). The results allow the identification in the mineral matrix of certain elements classified as critical raw materials (CRMs). Due to substitution effects, some scarce transition elements, such as Zn and Ni, are present and camouflaged in alkali silicate minerals, while others, such as Co, are included in ferromagnesian mineral phases. As expected, incompatible elements are preferably distributed on the surface of aluminosilicate mineral phases such as Rb and Ga, or exclusively in K-bearing feldspar phases, as it is the case of Sr. Interesting CRMs such as Ti, Zr, and Nb are well individualized in oxides, as well as in sphene and apatite. The detected antagonistic chemical distribution between Ti and Fe, and the good spatial relation between Ti and Ca confirms that Ti is present as sphene and, in areas with absent Si, probably occurs as rutile. Nb has a distribution pattern quite similar to Zr and occurs due to substitution effects. It was possible to conclude that there is probable co-existence of Zr-REE-Nb in specific mineral phases such as apatite, zircon, and other Zr-oxides. These results evidence and confirm NS as a potential source of multiple industrial minerals and distinct scarce elements which are incorporated in oxide or phosphate phases that can be more effectively separated in the beneficiation process.
Vera Pires, L. G. Rosa, P. M. Amaral, A. Dionísio, and J. A. R. Simão
American Society of Civil Engineers (ASCE)
V. Pires, P. M. Amaral, J. A. R. Simão, and C. Galhano
Springer Science and Business Media LLC
Fernanda Carvalho, Pedro Sousa, Nuno Leal, Joaquim Simão, Elissavet Kavoulaki, Maria Margarida Lima, Teresa Pereira da Silva, Hugo Águas, Giuseppina Padeletti, and João Pedro Veiga
MDPI AG
The study of building materials constituting cultural heritage is fundamental to understand their characteristics and predict their behavior. When considering materials from archaeological sites, their characterization can provide not only relevant information for a broader understanding of the site and its importance and significance but can also increase knowledge about ancient materials and their performance. The Palace of Knossos is a very important archaeological site in the European history context, and its preservation benefits from the characterization of the constituent materials. Samples of mortars from this monument were collected under the scope of the H2020 HERACLES project, where a multi-analytical approach was chosen using established protocols for the different sample typologies. Instrumental techniques such as optical microscopy (OM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and simultaneous thermogravimetry and differential thermal analysis (TG–DTA) were used for the chemical, mineralogical, and morphological characterization of these mortar samples. The results indicate that the majority are lime mortars, both aerial and hydraulic, but gypsum-based mortars were also identified. Differences in the chemical composition of the samples in distinct areas of the monument allowed us to reflect on the variety of materials used in the construction of the Palace of Knossos.
Carlos Galhano and João Elias
Knowledge E
Population expansion, especially in metropolitan areas, has led to an increase in the production of urban solid waste (USW) by domestic and commercial activity in urban centres. Reducing the production of these wastes is an extremely difficult task. However, the reduction processes, themselves, have the potential to produce a number of useful residues. This study focuses on the residues of incinerated USW, which produces ashes of varying compositions. This study investigates a mixture of two ashes, one resulting from the incineration of USW from LIPOR II (Intermunicipal Waste Management Service of Porto Region) and another from ValorSul (Valorisation and Treatment of Solid Waste of Lisbon and West Regions), both processed by EcoInCer (Ecological Innovations Ceramics company). Ashes from several samples of USW incorporating clays were tested to identify physical and mechanical characterisations, with a view to identifying useful ecological ceramic materials which could be used by the ceramics industry. Ceramic samples with 0%, 10% and 20% of ashes were incorporated in a clay matrix composed of 5% kaolin and 95% red clay, and submitted to leaching alterability in Soxhlet Extractor. The obtained results demonstrate the ways in which the ash percentage and the firing temperature can be important in the alterability of a ceramic material.
 Keywords: Ceramic materials, Leaching, Urban solid waste
Joaquim Simão, Nuno Leal, and Carlos Galhano
Trans Tech Publications, Ltd.
Six Portuguese magmatic ornamental stones were submitted to Soxhlet experiments during 10,000 hours (approximately 416 days) in order to evaluate how the rain water affects the rock behavior as a dimension stone. Macroscopic alterations were observed in the rock fragments and chemical analysis of leaching water solutions revealed how major elements were mobilized from rock-forming minerals allowing to compare weathering susceptibilities between different natural stones.
Ainara Zornoza-Indart, Paula Lopez-Arce, Karima Zoghlami, Nuno Leal, and Joaquim Simão
Informa UK Limited
ABSTRACT Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol–gel, Ca(OH)2, and SiO2 nanoparticles. These were subjected to marine aerosol accelerated aging cycles and studied by several non-destructive tests and techniques to assess the stability of the products. Results show that weathering caused by salt crystallization is not inhibited but it is slowed down due to the enhancement of superficial mechanical properties (surface cohesion and micro-hardness) achieved after one month of treatments application. A high or low relative humidity of the consolidation environment significantly affects the final mechanical and aesthetical physical properties and therefore conditions the durability of the treated substrates, even producing higher damage than observed in the blank specimens, depending on the product.
Cristina Carvalho, Zenaide Silva, and Joaquim Simão
Springer Science and Business Media LLC
Raul Alves, Paulina Faria, and Joaquim Simão
Elsevier BV
Ainara Zornoza-Indart, Paula Lopez-Arce, Nuno Leal, Joaquim Simão, and Karima Zoghlami
Elsevier BV
B. Sena da Fonseca, A. Vilão, C. Galhano, and J. A. R. Simão
Informa UK Limited
Abstract This paper aims at studying the influence of different clay/coffee waste mixtures in structural ceramics by incorporating different amounts of spent coffee grounds as an additive. Clay paste with 5, 10, 15 and 20 wt-% of coffee waste was used to mould clay bodies, which were then fired at the temperatures of 900, 1000 and 1100°C. Morphological aspects were evaluated through SEM images, while several laboratory tests provide the physical and mechanical properties. Incorporation of coffee waste increases the water absorption and apparent porosity, and increasing the firing temperature causes an overall decrease in pore size. Samples with up to 10% coffee waste are in the highest grade of mechanical strength standards. The addition of 20% decreases by 70% the thermal conductivity value. The coffee waste residues could be used as a secondary clay raw material to form proper bricks with excellent thermal insulation proprieties.
Zenaide Carvalho G. Silva, Joaquim A.R. Simão, Maria Helena Sá, and Nuno Leal
Trans Tech Publications, Ltd.
Seven silicate rocks used as ornamental stones and having different surface finishing were submitted to salt fog atmospheres in order to compare different susceptibilities to alteration. Polished, honed, hammered and flamed finishing types were tested. Rocks come from Portugal, Brazil and Angola and are widely commercialized. Samples covered quartz rich rocks, silica saturated and undersaturated rocks, mono and plurimineralic rocks, coarse and fine grained rocks. Mineral composition, texture and open porosity showed to be important parameters which determine mass loss among samples, but the finishing type was very effective within samples. Mass loss and porosity increase are higher on hammered samples, contrasted with the lowest loss values on polished samples. The effect of surface hydrophobicity and roughness on the samples having polished finishing was also analysed by atomic force microscopy (AFM) and water contact angle (WCA), indicating that texture and mineral diversity influence the hydrophobic character of the rock surfaces.
Vera Pires, Z.S.G. Silva, J.A.R. Simão, C. Galhano, and P.M. Amaral
Elsevier BV
Z.S.G. Silva and J.A.R. Simão
Elsevier BV
Manuel A.G. Silva, Zenaide C.G. Silva, and Joaquim Simão
Elsevier BV
J. Simão, E. Ruiz-Agudo, and C. Rodriguez-Navarro
Elsevier BV