FCT: DCT - Documentos de conferências internacionais
URI permanente para esta coleção:
Navegar
Entradas recentes
- Use of Industrial Waste for the Optimization of Ceramic Construction MaterialsPublication . Galhano, Carlos; Lamas, Pedro; Seixas, Diogo; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e GeotecnologiasThe massive growth of the ceramic industry and the consequent demand for construction materials worldwide has motivated the search for alternative solutions aimed at reducing the use of mineral/natural resources as the main source of raw materials. One of the strategies frequently adopted by the scientific community is the reuse of industrial waste. It is beneficial not only to reduce the overexploitation of mineral resources but also to reduce the environmental, economic and social impacts resulting from their incorrect disposal/treatment and consequent deposition on land unsuitable or that purpose. Duetoconsiderationssuchasphysico-mechanical characteristics and the high production rate, two different types of industrial waste were selected for this work, ashes resulting from the burning of coal in thermoelectric power plant, commonly known as bottom ash (B), and the Marble Powder (MP). It was intended to test the technological feasibility of the manufacture of ceramic materials produced from clay mixtures containing these two residues.For this purpose, the fine fraction(<63μm) obtained from the sieving of the marbleresidue(MR) and slag(Bf) was used, as well as a coarser grain slag fractionr anging from 63-125μm(Bg).The resulting test samples were subjected to a firing of 950 °C under an oxidizing atmosphere, following a primary drying process. Faced with the standard values, the new ceramic materials obtained from MP have seen their mechanical and porous characteristics decrease and increase, respectively. At the same time, although the addition of B in no way influenced the mechanical characteristics, a significant improvement the porous characteristic was observed. The incorporation of these residues produced a color very close to the original sample material.Keywords: industrial waste, ceramic, construction materials, bottom ash, Marble Powder
- Multibody simulations of diplodocid tail motionPublication . Conti, Simone; Tschopp, Emanuel David; Sala, G.; Mateus, Octávio; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias
- Control of compaction on embankment dam core by nuclear density meter and sand cone testPublication . Blanco, Luis; Santos-Ferreira, Alexandre; Silva, Paula F. da; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e GeotecnologiasSoil compaction is an essential stage in the construction of earth dams, through the course of history there have been several reports on dam failures that can be linked to inappropriate compaction. Therefore it is essential to evaluate the state of compaction achieved in the field, two commonly used methods to evaluate it are the conventional and nuclear methodologies. The conventional methodology consists in using the sand cone test to access the wet unit weight and the oven method to determinate the fill water content, in the nuclear methodology these parameters are measured with a nuclear density gauge. However in some countries the accuracy of the nuclear gauge measurement relatively to the conventional methodology has been questioned. The present paper establishes a correlational analysis between the results obtained with the sand cone test and the nuclear density-meter, these tests were executed during the quality control operation employed at the trial embankment of an earth dam.
- The Late Triassic of Jameson Land revisitedPublication . Mateus, Octávio; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias
- Recycling of CDW and Steel Slag in Drainage Layers of Transport InfrastructuresPublication . Roque, A. J.; Da Silva, P. F.; Rodrigues, G.; Almeida, R.; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e GeotecnologiasUsing waste as a civil engineering construction material represents an important environmental and economic advantage. In this context, it was studied the durability and permeability of a crushed concrete recycled aggregate (CCCDW), processed from construction and demolition waste (CDW), and an inert steel aggregate for construction (ISAC), processed from electric arc furnace (EAF) steel slag, with the aim to evaluate the technical feasibility of their recycling in the drainage layers of transport infrastructures. The durability of recycled materials was studied using the slake-durability test (SDT) proposed by International Society for Rock Mechanics (ISRM). In order to test the behaviour of the material in mechanical conditions more adverse than those specified in the ISRM method, more 600 rotation cycles than those foreseen in the original method were applied. As a complement to SDT tests, macro- and micropetrographic observations as well as physical characterizations of two recycled materials, both before and after SDT tests, were performed. Regarding the hydraulic behaviour of the recycled materials, constant-head permeability tests were carried out on specimens prepared from grain-size fractions in the ranges 0.25-2.0 mm and 2.0-20.0 mm. In the study was compared the behaviour of two recycled materials with two reference natural materials, a basalt and a limestone. The results obtained show, for the conditions tested, the technical feasibility of their recycling in the mentioned applications.
- Dredging of Vila do Conde harbor, Portugal - Contamination of sedimentsPublication . Santos-Ferreira, Alexandre; Dias, Elisabete; Silva, APF da; Santos, Cláudia; Cabral, Mónica; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e GeotecnologiasIn Portugal, the dredging of small harbors represents the main exploitation cost for these infrastructures. These costs can significantly increase depending upon the degree of sediment contamination, as their disposal can concern an important amount of the overall costs. Therefore, a methodology for zoning the contamination areas was developed and it is summarized. This methodology was applied to the dredged material of an ancient wharf, used since the Middle Age, at Vila do Conde harbor, North of Portugal. Considering the resultant contamination zoning, for different years, an evolution analysis of the contaminated areas before and after dredging operations was carried out. This approach intended to evaluate if the contaminated areas are similar after dredging operations in order to identify the possible contamination sources and, subsequently, to eliminate them. Thus, an important part of the dredging cost may well be reduced, since the elimination, or reduction, of contamination sources in a harbor can increase the environmental beneficial use of the dredged sediments.
- Geotechnical and Geological Characterization and Ambient Vibration Study of Shallow Geological Units in Barreiro and Setubal Areas (Portugal)Publication . Vicêncio, Henrique; Teves Costa, Paula; Sá Caetano, Paulo do Carmo de; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e GeotecnologiasBarreiro and Setubal are two regions located within the Metropolitan Area of Lisboa (Portugal) that may suffer from high losses due to earthquake occurrence. The objectives of this study were to evaluate the relationships between the geological and geotechnical properties of the shallower units with horizontal-to-vertical spectral ratio (H/V), looking for potential side effects. The geotechnical characterization was based on the analysis of 4064 Standard Penetration Tests (SPT) compiled in 676 boreholes of 96 geotechnical reports. Fundamental (F-0) and predominant (F-1) frequencies and corresponding amplitude peaks were obtained with 249 ambient vibration records carried out with a Guralp CMG 6TD broadband station. Data regarding SPT, thickness of surface units (Holocene), depths of the substrate (Pliocene and Miocene), F-0 and F-1 and respective amplitude peaks were analysed. The thickness of Barreiro Holocene (anthropogenic and alluvial deposits) was related to F-0, F-1 and SPT values. The spatial distribution of F-0 and F-1 allowed the definition of two surfaces. The first one corresponds to the boundary between the Holocene and the Pliocene (4-32 m deep) and the second one to the boundary between the Pliocene and the Miocene (250 m deep). Three areas prone to seismic amplification with frequencies between 2.5 to 8 Hz were identified. In Setubal, it was not possible to establish a relationship between the thickness of the surface units and F-0 and F-1.
- The importance of electron microscopy in MicropaleontologyPublication . Legoinha, Paulo
- Mastodonte em depósitos marinhos da Praia do Penedo (Portugal)Publication . Antunes, M. Telles; Mazo, AV; Legoinha, PO achado de um dente de mastodonte, cf. Tetralophodon longirostris, em depósitos marinhos expostos na praia de Penedo Norte, na Península de Setúbal, permitiu datação rigorosa. Provém da camada 8 do corte, parte basal da sequência deposicional T1; data do início do Tortoniano, ca. de 11.6 Ma, com base em foraminíferos planctónicos (zona N14) e em 87Sr/86Sr e K/Ar. O dente de mastodonte parece pertencer a Tetralophodon longirostris, espécie conhecida em Portugal em depósitos continentais da primeira parte do Miocénico superior.
- The neogene of Algarve: excursion 2Publication . Antunes, M. Telles; Elderfield, H.; Legoinha, P.; Pais, João