C-MADE

Reinforced concrete beams subjected to pure torsion

2011-11-10T01:07:00.000Z

The global behaviour of reinforcedconcrete beams subjected to pure torsion is studied in this thesis. This studyincludes beams that have a rectangular cross section (plain or hollow), andmade with normal and high strength concrete. Longitudinal and/or transversalprestress is also considered. The theoretical study is based on the space trussanalogy with variable angle by considering nonlinear behavior of the materials.This model was initially applied in its original formulation to study theultimate behavior of the beams. Afterwards, this model was modified in order topredict the overall behavior of the beams under torsion, from the beginning ofloading up to failure.
Various constitutive laws proposed by several authors and found inthe bibliography were tested in order to characterize the behavior of concretein compression on the struts as well as the behavior of the reinforcement intension (for both normal and prestress reinforcements). The softening and thestiffening effects were included in the analyses.
To support the study carried out throughout this work, twocomputer applications were developed by using the programming language DELPHI.The first application (TORQUE_MTEAV) was developed for the first phase of thework and was used to study the ultimate behavior of the beams under torsion.This application was based on the space truss model with variable angle byapplying its original formulation with the consideration of variousconstitutive laws for the materials. The second application (TORQUE_MTEAVmod)was developed for the second phase of the work and was used to study the globalbehavior of the beams under torsion. This application was based on a modifiedspace truss model with variable angle.
In order to evaluate the adequacy ofthe theoretical models and of the implemented modifications, the theoreticalpredictions were compared with experimental results from various studies foundin the bibliography. After this analysis, the best theoretical predictions werealso compared with the predictions from some codes of practice in order toevaluate the degree of optimization of the theoretical models when used forproject. A simple computer application (TORQUE_DESIGN) was also developedfor this purpose.
Doctoral Thesis in Civil Engineering of Jorge Andrade, 2011 (pdf available soon at www.cmade.ubi.pt)

Experimental study of an innovative element for passive cooling of buildings

2011-07-07T00:41:00.008+01:00

The use of passive cooling techniques has been seen as one of the solutions that can help to reduce energy consumption in the building sector. An innovative element that allows the combined use of two of the passive cooling techniques most mentioned in recent literature, evaporative cooling and night ventilation, is proposed in the present work. The combined application of passive cooling techniques can help to overcome the limitations resulting from their isolated application, which, in general, results from local climatic conditions. In order to optimize the use of those techniques it was decided to include in the element configuration a core component with latent heat storage capabilities. The presence of this core component makes it possible to suit the cooling processes occurrence with its demand and also enables cooling rates not necessarily equal to production ones. Thus the innovative nature of the proposed element results from the combination of evaporative cooling with latent heat storage, and with night ventilation. The present work includes the conception, development, construction and experimental studies of a prototype of this element. Briefly it can be said that the element is composed by the accumulating core, consisting of a mortar vertical panel impregnated with paraffin, with two adjacent channels for air circulation. The element, whose configuration should allow its integration into the buildings envelope, has a parallelepiped shape with one air inlet and one air outlet in each of its opposite faces, the exterior and the interior ones. The airflow in each channel is provided by tangential fans mounted on top of the element. The paraffin wax used corresponds to a commercial wax with phase transition range near 20 ºC, slightly below typical comfort temperatures. After its construction, the prototype of the element was subjected to a series of experimental studies that aim to know its response in operating conditions similar to real ones. These studies took place in a climate chamber for a wide range of conditions. The results suggest that the proposed element exhibits the potential for passive cooling of buildings. It was concluded that the paraffin wax incorporation in the mortar core has substantially improved the capacity of thermal energy accumulation of the element, that the evaporation process on the outside surface of the core provides a substantial temperature reducing of the core, and that its use also during night periods allows to cool the core well below the outside temperatures, thus maximizing the possibility of application of night ventilation.

Doctoral Thesis in Mechanical Engineering of Luís Carlos Carvalho Pires, 2011 (pdf available soon at www.cmade.ubi.pt)

GEOGREEN - Waste geopolymeric binder-based natural vegetated panels for energy-efficient building green roofs and facades

2011-06-07T23:00:00.016+01:00

Green roof utilisation has been known since ancient times both in hot and cold climates. Nowadays, it has been reconsidered at issue of energy saving and pollution reduction. Green roofs and facades delivery multiple benefits. It creates a modern, unique aesthetics and building envelope that is living and changing with time. It enhances building’s energy rating. It provides natural shading and cooling in summer and, in some cases, thermal insulation in winter through its external wall insulation layer.

Green facades and green roofs typically have different layers of construction; a protection layer, a drainage layer and a growing media (soil). The most important characteristics of the growing layer are its thermal conductivity, specific heat capacity, and density. Depending upon the type of vegetation used the growing media layer may be as thin as 5 cm or as thick as 1m, thus the media layer has significant implications for the construction of the building and roof or façade support system. Additionally, selection of adequate growing vegetation, irrigation system and water management, leakage-proof protection, among others, are also relevant aspects for thermal and energy performance, as well as construction details, of such passive cooling technologies.

Currently, there are numerous research works in progress in this field and a worldwide growing interest in utilization of green roofs and facades, particularly in Europe, as climate and energy security concerns have come to the forefront of EU policymaking. This is also CMADE research focus, contributing for the investigation of building materials and technologies environmentally sustainable, having multidisciplinary competences to tackle research in this field.

Therefore, this project will carry on an interdisciplinary original study for the development of green roof and facades. Originality of this proposal resides in the fact that research intends to develop an pre-fabricated panel, incorporating vegetation, as part of a modular building system, that can be easily adapted to new buildings and retrofitting, being as well, easy to replace and maintained in normal functioning.

The project will be supported by a cell test infrastructure were real climate studies will be carried on. The cell test, during the duration of this project, will be placed at Beira Interior Region where occurs large temperature differences between summer and winter, which will be of particular interest to the application of this studies in both Portugal and Europe.

Project: PTDC/ECM/113922/2009

Total Funding:€ 152.832,00

Starting Date: March 2011

INTERDISCIPLINAR SEMINAR : Polymer-based composites using mining wastes: Technical-artistically applications

2010-11-11T22:22:00.013Z

University of Beira Interior

23 of November 2010. Faculty of Engineering. Conference Room 8.01

In Europe, about half the wastes produced by industry are from mining, which accumulate in heaps in some locations/regions, and its potential for re-utilization in conditioned by various factors, although it is an abundant reusable and low cost raw material. In Portugal, the mine waste accounts for approximately 20% of the total industrial waste accumulated. In the Central Region of Portugal, is located one of the most important of tungsten mines in the world, Panasqueira mines, which were recently the subject of an innovative research project aiming at reuse of its tailings as building materials for new technical and artistic applications.

In this context, the University of Beira Interior promotes an Interdisciplinary Seminar in collaboration with companies, technicians and researchers about the potential development of new composites, produced using wastes from mines and quarries, and its possible applications, in perspective of sustainable construction, waste reuse, innovation and economic viability in sculptural and architectural applications having great aesthetic value.

The Seminar will be held in Portuguese and Spanish language.

Programme:

09:30h – Opening

Mário Marques Freire, President of Engineering Faculty

09:50h – João Moura Bordado (Instituto Superior Técnico):

“REACÇÕES DE POLIMERIZAÇÃO E PRODUÇÃO DE POLÍMEROS PARA MATERIAIS COMPÓSITOS”

10:10h – Teresa Baptista (Grupo ACA Engenharia, S.A.):

“PAVIMENTOS COLORIDOS COM INCORPORAÇÃO DE RESINAS"

10:30h – Rafael Peralbo Cano (University of Granada):

“MORTERO Y HORMIGÓN: TECNOLOGÍA Y APLICACIONES ARTÍSTICAS”

10:50h – COFFE

11:00h – João Castro Gomes (University of Beira Interior):

“NOVOS MATERIAIS DAS ESCOMBREIRAS DAS MINAS DA PANASQUEIRA”

11:20h – Abílio Silva (University of Beira Interior):

“APLICAÇÕES DE MATERIAIS COMPÓSITOS COM RESÍDUOS DE MINAS”

11:35h – Pedro Dinho Silva (University of Beira Interior):

“PROPRIEDADES TÉRMICAS DE MATERIAIS COMPÓSITOS RECICLADOS”

11:50h – Jorge Alberto Durán Suárez (University of Granada):

“MATERIALES PÉTREOS EN ESPACIOS PÚBLICO VS ARTE: CONSERVACIÓN Y RESTAURACIÓN”

12:10h – Carlos Reis Figueiredo (Reis Figueiredo – Arquitectos da Beira, Lda.)

“A MATERIALIDADE NA CONCEPÇÃO ARQUITECTÓNICA”

12:30h – Debate and Conclusions

Preheating the ventilation air by a ventilated double window

2010-04-11T12:02:00.007+01:00

The need to ensure indoor air quality in all buildings it requires air renovation through ventilation. The outgoing air removes warm from inside the building in the winter and the income cold air may result in local thermal discomfort. These thermal losses due to ventilation, results in energy consumption. One way to reduce the inconvenience of undesirable and uncomfortable cold ventilation, associated to heating energy consumption needs is to pre-heat de incoming air with passive systems.
To reduce thermal loss and cold air infiltration in colder zones of Portugal, traditional Portuguese fenestrations are being doubled by a second single glazed window on the outside of the pre-existing window. The air channel between windows is therefore not ventilated. Adding vents at the bottom of the outer window and at the top of the inner window creates a path for incoming airflow through the gap. This ventilated double window is a passive heating system that provides pre-warmed air for winter ventilation, then otherwise would enter the building at outdoor’s temperature.
A study was carried out at the UBI to investigate the performance of a ventilated double window to preheat ventilation air. This air is pre-heated within the air channel between the windows by heat that is lost from the building and also by solar gains. It is delivered inside warmer than it is outside. Tests were conducted under outdoor weather conditions and considering exclusively natural ventilation.
Experimental work on a south-facing test cell facility tested several full-scale configurations of the ventilated double window being monitored for a range of weather conditions. Furthermore a parametric analysis was used to determine the performance of this passive heating system. The outlet temperature and useful heat gains of the system were plotted as a function of ambient temperature difference, incident wind and solar radiance. This had shown that the results are particularly sensitive to the modelling of the inlet temperature and incident solar radiation.
The case study was used to understand the principles behind operation of this ventilated double window, which works as a heat recover and also as solar collector.However, it is a highly dynamic passive system, reacting to the climatic changes that come across; namely the air temperature, wind and solar radiation, so the system’s success depends on several associated characteristics, like place and the design of the building.
Doctoral Thesis in Civil Engineering of Jorge Manuel da Silva Carlos, 2010 (pdf available soon at www.cmade.ubi.pt).

Recent laboratory equipment avaliable for research

2010-02-05T13:58:00.011Z

Main laboratory equipments available at C-MADE are dedicated to study properties and performance of building materials. Such equipments and facilities can be utilized by researchers from others Universities/Research Centres.
The equipments listed were acquired under "Programa Nacional de Reequipamento Científico", co-financed by FCT - Fundação para a Ciência e Tecnologia and FEDER.

Preliminary results of alkali-activated fly ash generated from an electrical power plant in Rio Grande do Sul, Brazil

2009-09-13T22:43:00.006+01:00

New Method of Detection of HydrogenFly ash is a byproduct resulting of burning pulverized coal in electric power generating plants. Generally, fly ash can be used in concrete production, as cement partial replacement, improving concrete performance, particularly its durability. However, in Brazil, particularly at Rio Grande do Sul state, only a relatively small part of fly ash byproduct is being utilized by concrete industry due to its large generation by electric power plants. Thus, the main objective of this collaborative research work, between Prof. Alexandre Vargas of Feevale University and CMADE researchers, was to evaluate over time the development of the compressive strength of alkali-activated fly ash mortars. A combined solution of NaOH and Ca(OH)2 was used as alkaline activator. The curing of the samples was carried out in two distinct ways. In the first one, samples were kept at 70°C during the first 12 hours after mixing and at 22°C afterwards, until the age of testing. Although compressive strengths of about 20 MPa were achieved during the first 24 hours, the strength started to decrease after 7 days. Considering this behaviour, a second method of curing was adopted. The mix proportions were the same as before, however the mortar samples were kept in an oven at 70°C until the age of testing. In this case, the compressive strength values decreased more significantly and in a shorter period of time, as compared to the results obtained for samples cured using the first method. Complementary studies were performed in order to better understand the observed reduction in compressive strength. Microstructural analyses of the fly ash, before and after the alkali-activation, have been carried out using Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) at Optical Centre of University of Beira Interior. It was possible to identify three different morphologies in the alkali-activated pastes: one composed by regions with dense aspect; other showing partially solubilised particles of fly ash; and a third showing the formation of products with a needle-like shape. The information provided by the SEM/EDS experiments was not enough to enable the complete understanding of the mechanism of the deleterious reaction that took place among the alkaline activators and the fly ash. Therefore, future studies should address this question by using additional analysis tools in order to clarify this deleterious mechanism.
Ongoing research coordinated by Prof. Alexandre Vargas (Feevale University, Brazil) in collaboration with CMADE researchers.

Study of moisture damage (by water immersion and freeze thawing conditioning) in warm asphalt recycling

2009-07-04T17:12:00.007+01:00

Environmental factors and traffic load contribute to early failures in bituminous pavements. Moisture is a key element in the deterioration of the asphalt mix. It can degrade the integrity of pavement by loss of cohesion (strength) and stiffness of the asphalt film, failure of the adhesion between the aggregate and asphalt (stripping) and degradation or fracture of the aggregate, particularly when the mix is subjected to freezing.
This work studies moisture damage (by water immersion and freeze-thaw conditioning) in asphalt pavements. The methodology used is well known among engineering pavement experts, however, this is a case of a novelty research work, since the study is about water sensitivity and freeze-thaw damage of warm recycled bituminous mixtures.
Water Sensitivity was studied according to European Standards EN 12697-12:2003 and EN 12697-23:2003 by measuring the indirect tensile strength of bituminous specimens, as well by Immersion-Compression Test carried out according to the Spanish Standard NLT-162/00.
The resistance to moisture damage by freeze-thawing conditioning was also determined by ASTHO T283.
A new method based on ultrasonic accelerated moisture conditioning was also proposed, demonstrating to be as well as effective to evaluate the moisture sensitivity, having the advantage of being executed in a shorter period of time.
Tests were carried out in laboratory compacted specimens and taken of Portuguese roadway EN244, section between PONTE DE SÔR and the proximity of the GAVIÃO. This is a case of a Portuguese roadway rehabilitation using a new technology designated by WARM ASPHALT RECYCLING. The technology consists of removing the existing pavement structure, in a 7cm depth, by a ripping/crushing operation and producing a recycled mix in central plant consisting of 98% of reclaimed asphalt pavement and 2% of a cold emulsion. This recycled bituminous mix is produced at 130ºC, placed again in the roadway as replacement of the existing old pavement, and compacted at 90ºC. The reason this methodology is designated warm asphalt recycling is that temperatures used in process are lower than those used in hot asphalt recycling. The method was proposed by CEPSA and the work in EN244 roadway is being carried out by JJR Construções Lda, being follow up and developed by CMADE researchers and LNEC.
Results obtained have shown that warm asphalt recycled pavement has a very good resistance to water damage, when submitted to water sensitivity tests used in this research work.
Master dissertation in Civil Engineering of Maria João Torres, 2009 (pdf available soon at www.cmade.ubi.pt)

High –value of urban and industrial wastes in cementitious composites

2009-06-25T06:00:00.000+01:00

Studies for the feasibility of using recycled glass and ceramics in cementitious composites were carried out at CMADE. The importance of this study deals with the need to find viable alternatives for replacements of natural aggregate materials, which are scarce, and to reduce the residues deposited in landfill, thus reducing the environmental impact and allowing a more sustainable development.
The glass and ceramic wastes were studied as a partial replacement of cement in mortar. In concretes, glass waste was studied as a partial or total substitute of natural sand.
The experimental work was developed by studying the fresh and hardened properties of mortars and concretes, through the determination of consistency, compressive mechanical strength and evaluation of durability parameters. This evaluation was conducted by measuring the expansion of mortar and concrete bars. In case of concrete mixtures this evaluation was completed by capillarity absorption test, water and air permeability test.
From the experimental results, it was possible to conclude about the technical viability to produce pozzolans materials using this wastes. It was also concluded about the viability to use the glass waste as a partial or total replacement of the natural sand. The physical characteristics and limits of incorporation of waste materials as pozzolan and as replacement fine aggregates of natural sand were determined in this dissertation.
Master Dissertation in Rehabilitation and Construction Environment of Pedro Miguel Silva Santos, 2008 (pdf available soon at www.cmade.ubi.pt)

Emulsion based mixes using 100% mining wastes, for low traffic roads in rural areas

2009-06-22T15:06:00.000+01:00

In this work the composition of a emulsion based bituminous mixe was studied using 100% recycled waste materials of wolfram mines (Panasqueira Mine, located at Centre Region of Portugal). Physical and mechanical characteristics of this mixe and its low cost, was considered to be an adequate solution in pavement of roads having low traffic volume, namely municipal and rural roads. The use of waste materials of Panasqueira as replacement of natural aggregates, in bituminous mixtures, as it is considered in this work, constitutes a partial solution for the consumption of the millions of tons of wastes deposited, thus reducing the environmental impact and as well reducing the production cost of the bituminous mix.
This emulsion based bituminous mix, because of its low cost, is presented to local councils as a cheaper solution for maintenance, improvement and pavement of secundary roads, namely municipal roads in rural areas.
The option for a cold open mix is justified by the lesser energy consumption and by the increasing interest on the problems of environmental pollution. Moreover, the cold technology, based on the emulsion use, has had an increasing evolution all over Europe, following chemical improvement of such products and offer different type of emulsions, providing technicians with an efficient, versatile and economic instrument.
As for the laboratorial work, a physical and mechanical characterization was performed on local natural aggregates and on the waste materials of Panasqueira mine. Several trial mixes were manufactured and compacted using different emulsion contents, controlling its properties with cantabro and permeability tests, to obtain optimal proportions.

Master Dissertation in Civil Engineering-Construction of Marisa Sofia Fernandes Dinis de Almeida, 2003 (available in Portuguese)

Laboratory studies of thermal rehabilitation of masonry stone walls of rural houses

2009-06-19T20:16:00.000+01:00

It is well known the traditional rural houses of Portugal are constructed using traditional materials such as timber and masonry. The use of these materials results in poor thermal isolation as well as low resistance to water penetration.
As a result, these houses are often found in a deteriorated state. Thus it is necessary to find solutions to rehabilitate the structure, specifically the roof, masonry walls and timber floors.
Those solutions are necessary to improve living conditions particularly hydrothermal comfort, but must maintain their architectural/construction characteristics and the use of traditional materials.
Having this in mind, the main object of research was to study several different construction solutions for thermal rehabilitation of masonry walls.
During the first phase of the work, an analysis of the risk of condensation was carried out using the Glasser method for a number of current thermal rehabilitation construction solutions.
Later, having taken into account these results, a laboratory study was carried out in a climatic chamber in which variations of temperature and relative humidity occurred in a thermal rehabilitated masonry wall using some of solutions in the first phase were measured.
It is believed, the results of this work can contribute to a better understanding of hydrothermal behaviour of inside thermal rehabilitated masonry walls using construction solutions that reduce condensation risk.
Master Dissertation in Civil Engineering-Construction of Paulo Alexandre Martins Moradias, July 2008, (pdf avaliabe soon at www.cmade.ubi.pt)

SELICON - Vida útil de projecto e modelação do desempenho da durabilidade do betão

2009-06-16T17:12:00.006+01:00

O projecto SELICON é um projecto de investigação financiado pela FCT que visa estudar e propor modelos de dimensionamento da vida útil de projecto com base no desempenho da durabilidade do betão. Espera-se que os resultados deste projecto permitam vir a dispensar-se o uso de critérios prescritos para o projecto de vida útil, como por exemplo a razão A/C máxima, adoptando-se em sua substituição um modelo de durabilidade do betão baseado no seu comportamento material e estrutural após a iniciação da corrosão. Assim, neste projecto, pretende-se por um lado, determinar indicadores de durabilidade com base em ensaios experimentais, para uma amostragem representativa de tipos de betão e de condições de exposição, mais correntes em Portugal. E, por outro lado, o trabalho de investigação será centrado no desenvolvimento de novos modelos, com uma abordagem integrada, que melhor traduzam as alterações do material betão e o seu desempenho estrutural, na fase de propagação da corrosão.
O Projecto SELICON, financiado parcialmente pela FCT, será desenvolvido por investigadores da Universidade do Minho, do LNEC e do C-MADE/UBI, contando também, para já, com o apoio de algumas empresas, como o IEP, bem como de vários consultores estrangeiros.
Um dos principais objectivos deste projecto, de maior interesse prático, será o desenvolvimento de um software de fácil utilização, para o dimensionamento da vida útil de projecto e avaliação do desempenho de durabilidade de estruturas de betão armado, destinado aos engenheiros projectistas e investigadores do betão estrutural.

matcons - Mestrado em Materiais e Tecnologia da Construção (2ºCiclo) 2009/2010

2009-06-16T15:03:00.000+01:00

OBJECTIVOS:
Com recurso à investigação de carácter interdisciplinar pretende-se, com este mestrado, formar especialistas no domínio da engenharia civil e áreas afins, promovendo a inovação no domínio dos materiais e tecnologias de construção, ambientalmente sustentáveis, ou seja, protótipos de novos produtos e tecnologias de construção, mais duráveis, com melhor comportamento mecânico, ambientalmente sustentáveis e para o controlo de poluição, bem como na reabilitação e melhoria da eficiência energética de edifícios.

DESTINATÁRIOS:
O curso visa a formação de especialistas, com capacidade de desenvolver trabalho de investigação de inovação tecnológica, vocacionados particularmente para o ambiente empresarial, assim os seus principais destinatários:
- Estudantes do primeiro ciclo de Licenciatura em Ciências de Engenharia, de outras Licenciaturas afins, e de especialistas (Mestres) em outras engenharias tradicionais;
- Investigadores de instituições e centros de investigação, com competências e autonomia para prosseguir estudos de doutoramento, em ambiente académico ou industrial.
- Especialistas com experiência profissional que pretendam desenvolver competências nos domínios em que o curso se focaliza, em co-promoção com empresas e centros nacionais e internacionais, de investigação e desenvolvimento.

SAÍDAS PROFISSIONAIS:
- Sectores produtivos em empresas de materiais de construção e da fileira da construção;
- Actividades de acompanhamento, consultoria e apoio técnico especializado, em obras de engenharia civil;
- Desenvolvimento de áreas emergentes de empresas do sector da construção, como a energética de edifícios e a construção sustentável;
- Áreas de investigação e desenvolvimento ligadas à indústria dos materiais de construção;
- Sectores de investigação e desenvolvimento tecnológico da indústria da construção e reabilitação;
- Criação e novas empresas de base tecnológica – empreendedorismo;
- Consultoria e estudos técnicos multidisciplinares em ambiente internacional;
- Doutoramento e carreira docente ou de investigação em ambiente académico ou industrial.

PLANO DE ESTUDOS E CORPO DOCENTE:
1ºAno, 1º Semestre
Avaliação e Qualidade de Edifícios, 6 ECTS, Prof. João Carlos Lanzinha

Construção Sustentável, 6 ETCS, Prof. Luiz Pereira de Oliveira

Durabilidade dos Materiais, 6 ETCS, Prof. João Castro Gomes
Processamento de Materiais Compósitos, 6 ETCS, Prof. Abílio Silva
Técnologia de Betões Especiais, 6 ETCS, Prof. Miguel Nepomuceno

1º Ano 2º Semestre
Compósitos e Materiais Estruturais, 6 ETCS, Prof. Luis Filipe Bernardo
Empreendorismo de Base Tecnológica, 6 ETCS, Prof.ª Maria José Silva
Energética de Edifícios, 6 ETCS, Prof. Pedro Dinho Silva
Materiais para Controlo de Poluição, 6 ETCS, Prof. António Albuquerque
Seminários de Investigação em Construção, 6 ETCS, Director de Curso

2º Ano 1º Semestre
Inovação e Gestão Tecnológica, 6 ETCS, Prof. Tessaleno Devesas
Complementos de Probabilidade e Estatísitica, 6 ETCS, Prof. Dário Jorge Ferreira
Inglês Técnico, 6 ETCS, Prof.ª Paula Elyseu Mesquita
Dissertação Em Matcons, 42 ETCS, Director de Curso

DIRECTOR DE CURSO:
Prof. João Castro Gomes

Candidaturas até 31 de Agosto de 2009

AGREDUR lastest results

2009-06-15T20:45:00.006+01:00

In this research project concretes using different coarse aggregates of different geological sources, granite, basalt, calcareous and marble, were produced in specific mix proportions and laboratory controlled conditions. Aggregates used were of good quality, having low particle water absorption and relevant mechanical properties. The influence of coarse aggregate type, size, as well dry or water saturated conditions, on the concrete mechanical and durability parameters were determined.It was found that aggregates type, size or water content during mixing does not influence significantly concrete mechanical behaviour for a C30/37 concrete strength class.Regardless of aggregate type, concrete mixtures produced using larger size aggregates presented higher vacuum water absorption and oxygen permeability, than mixtures using smaller size aggregates. This might be explained by the fact that larger coarse aggregates in concrete contribute not only to the increase of path length of capillary pores and its interconnectivity, but also to the increase of cement-aggregate interface zone.Also regardless of aggregate type, concrete mixtures using saturated aggregates before mixing presented lower vacuum water absorption and oxygen permeability than mixtures were aggregates were introduced in a relatively dry state. It is likely that when aggregates are water saturated before mixing it does not absorbs water from the cement mortar fraction, and thus contributes to a dense cement aggregate interface. Consequently, if aggregate is dry it will absorb water contributing to a porous cement aggregate interface zone.Thus, it is beleived that concrete durability properties are not affected by aggregates mineralogy, but in turn are significantly affected by the aggregate size and its water content.

http://www.c-made.ubi.pt/prototypes-project1.html