NMM: Recent submissions

Now showing items 181-200 of 251

Estruturas de Betão Armado – Guia Técnico de Recomendações: Requisitos de Durabilidade, Processos de Degradação, Métodos de Inspecção e Reparação

Póvoa, A.; Santos Silva, A.; Tomás, Q. (Associação Portuguesa para a Segurança e Conservação de Pontes, 2011-06)

A presente comunicação pretende sintetizar o trabalho de pesquisa e compilação desenvolvido no seio do projecto DURATINET (Grupo de Trabalho 3 - WG3), designadamente no que se refere à elaboração de Guias com Recomendações ...
Degradação do betão por reacções álcalis-agregado: Exemplos de diagnóstico/prognóstico em pontes

Santos Silva, A.; Soares, D.; Matos, L.; Salta, M. M. (Associação Portuguesa para a Segurança e Conservação de Pontes, 2011-06)

A ocorrência, essencialmente na última década, de um grande número de estruturas de betão degradadas por reacções álcalis-agregado (RAA) em Portugal, motivou a necessidade de se avaliarem os métodos de caracterização da ...
Adição de metacaulino em betão - efeitos sobre a durabilidade

Santos Silva, A. (2011-06)
Metakaolin-lime hydration products and phase stability:

Gameiro, A.; Santos Silva, A.; Veiga, M. R.; Velosa, A. (ZAG, Slovenian National Building and Civil Engineering Institute, 2011-06)

Metakaolin (MK) is nowadays a well-known pozzolanic material being used in cement-based materials, like mortars and concretes. The reaction of MK with calcium hydroxide yields cementitious products, being the main phases ...
Natural consolidation of ancient historic buildings mortars submitted to humid and marine environment: a microscopic study

Borges, C.; Santos Silva, A.; Veiga, M. R. (ZAG, Slovenian National Building and Civil Engineering Institute, 2011-06)

Ancient historical buildings are important features of the history, culture and development of a country and its people. This study presents the results of chemical, physical and microstructural characterization performed ...
Inhibition of ASR and DEF: evaluation of the microstructure of concrete mixes with pozzolanic additions

Santos Silva, A.; Soares, D.; Matos, L.; Divet, L.; Salta, M. M. (ZAG, Slovenian National Building and Civil Engineering Institute, 2011-06)

The use of pozzolanic mineral additions is a known method to inhibit the expansive chemical reactions in concrete, like the alkali-silica reaction (ASR) or the delayed ettringite formation (DEF). The ASR is a chemical ...
Argamassas antigas. Produtos resultantes de reações químicas ao longo do tempo.

Magalhães, A.; Santos Silva, A.; Veiga, M. R. (2011-05)

As modificações sofridas pelas argamassas de revestimento ao longo do tempo são acompanhadas de rearranjos químicos e físicos na sua estrutura, bem como de alterações nas suas propriedades químicas e físicas. Várias reações ...
Argamassas resistentes ao tempo: abordagem microestrutural de fortificações portuguesas

Menezes, P.; Borges, C.; Santos Silva, A.; Menezes, A. P.; Veiga, M. R. (2011-05)

O complexo de fortificações de Cascais, litoral centro-sul de Portugal, foi erguido a partir do século XVI com a intenção de reforçar a defesa marítima da Vila e porto de Cascais, ao temer-se que as forças castelhanas ...
Evaluation of pozzolanic reactivity of artificial pozzolans

Pontes, J.; Santos Silva, A.; Faria Rodrigues, P. (Escola de Engenharia da Universidade do Minho, 2011-04)

Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. This property results from the reaction between calcium hydroxide and silica and alumina based ...
Historical Heritage: A study to conservation

Borges, C.; Santos Silva, A.; Veiga, M. R.; Borsoi, G. (Escola de Engenharia da Universidade do Minho, 2011-04)

Considering ancient monuments and historical buildings, it seems that these mortars have proved to be durable and reliable materials. The restoration and maintenance of old renders is one of the key aspects of correct ...
Behaviour of glass in cement-based materials: Its role on ASR

Serpa, D.; Santos Silva, A.; Soares, D.; Santos, M. B.; Brito, J. (Escola de Engenharia da Universidade do Minho, 2011-04)

One of the most worrying degradation mechanisms in hardened concrete is the occurrence of chemical expansive reactions, namely due to alkali-silica reactions (ASR). This pathology involves the formation of expansive products ...
Alkali-Aggregate Reactions in concrete: Methodologies applied in the evaluation of Alkali Reactivity of Aggregates for concrete

Santos Silva, A.; Soares, D.; Fernandes, I.; Salta, M. M. (Escola de Engenharia da Universidade do Minho, 2011-04)

The alkali-aggregate reaction (AAR) in concrete is a group of chemical reactions that involves the reaction of certain minerals present in the aggregates with alkali and hydroxyl ions in the interstitial solution of cement ...
The influence of slaking time on lime putty

Margalha, G.; Santos Silva, A.; Veiga, M. R.; Brito, J. (Universidade do Porto, 2011-04)

A new interest in the preservation of mortars, plasters and decorative finishings in façades has emerged in certain European countries in the past thirty to forty years, with a view to understanding how they have evolved ...
Phase and microstructural characterization of lime-MK blended mixes

Gameiro, A.; Santos Silva, A.; Veiga, M. R.; Velosa, A. (Escola de Engenharia da Universidade do Minho, 2011-04)
Mitigation of Internal Expansive Reaction: the role of Tungsten Mine Sludge

Sousa, S.; Santos Silva, A.; Velosa, A.; Gameiro, A.; Rocha, F. (Escola de Engenharia da Universidade do Minho, 2011-04)

The concrete degradation caused by internal expansive reaction (IER) is a problem that affects many structures in the world. These reactions, which include the alkali-silica reaction (ASR) and the internal sulphatic reaction ...
Use of tungsten mine sludge waste in the mitigation of internal expansive reaction

Sousa, S.; Santos Silva, A.; Velosa, A.; Rocha, F. (universidade do Porto, 2011-04)

The degradation of concrete structures by the internal expansive reactions (IER), which include the alkali-silica reaction (ASR) and the internal sulphate reaction (ISR) related with delayed ettringite formation (DEF), are ...
Effect of inorganic content on the performance of anticorrosive hybrid sol-gel coated EN AW-6063 alloy

Fontinha, I. R.; Salta, M. M.; Zheludkevich, M.; Ferreira, M. G. S. (Materais 2011 - SPM, 2011-04-18)

The organic-inorganic hybrid sol-gel films have been reported as an effective anti-corrosion and environmentally friendly alternative to Cr(VI) pre-treatment for aluminium alloys. These hybrid materials, constituted by ...
Modeling the start of the expansion due to alkali silica reaction in concrete

Gonzalez, L.; Santos Silva, A.; Soares, D.; Jalali, S. (lnec, 2011-02)

Service life of a concrete affected by alkali-silica reactions (ASR) is the age at which expansion is no longer allowed for normal use of a structure; such expansion level depends on the application. Once the induction ...
Expansion tests for alkali-reactivity of aggregates – a comparison based on a kinetics approach

Gonzalez, L.; Santos Silva, A.; Jalali, S. (LNEC, 2011-02)

The reactivity of aggregates regarding the alkali-silica reaction (ASR) has been measured by different properties affected by the reaction. One among those properties is the expansion measured by linear dilatation of mortar ...
Laboratory and microstructural tests on the detection and prediction of AAR

Santos Silva, A.; Fernandes, I. (LNEC, 2011-02-14)

LNEC has been involved in research dealing with alkali-aggregate reactions for the past 20 years. In recent years, the research has been directed at identifying the magnitude of the problem in Portugal, identifying rock ...

Now showing items 181-200 of 251

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