Página 1 dos resultados de 65 itens digitais encontrados em 0.002 segundos

Desenho do processo e qualidade na construção do painel monolitico de solo-cimento em taipa de pilão; Drawing of process and quality in the construction of monolithic panel of soil-cement in rammed earth

Andre Falleiros Heise
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/06/2004 PT
Relevância na Pesquisa
67%
O universo da construção civil vem se tornando o foco principal das pesquisas científicas e tecnológicas nos diversos campos do conhecimento humano, por ser um dos responsáveis pelo alto grau de problemas ambientais e sociais. Através da inovação tecnológica é possível diminuir estes problemas, utilizando processos que geram poucos resíduos poluentes e incluem as pessoas em seus processos, melhorando as condições e a qualidade de vida da população. Os principais objetivos deste trabalho são: mapear, identificar etapas, calcular suas médias produtivas e propor melhoramentos para o processo de produção do painel monolítico de solo-cimento em taipa de pilão. O autor investigou cinco canteiros de obra que utilizaram a tecnologia de construção do painel monolítico de solo-cimento, mapeou os canteiros de obra, identificou os painéis e as atividades do processo, bem como as ferramentas e equipamentos, materiais e mão-de-obra e as informações necessárias; identificando finalmente a ocorrência de não conformidades. A partir da investigação do processo foi possível indicar possibilidades de melhorias com o investimento em equipamento, treinamento e qualificação de mão de obra e utilização de procedimentos de execução e de controle de qualidade das atividades. E para as etapas do processo foram calculadas as médias produtivas e através das tabelas e gráficos foram analisadas as produtividades do processo...

Soil stabilisation using alkaline activation of fly ash for self-compacting rammed earth construction

Cristelo, Nuno; Glendinning, Stephanie; Miranda, Tiago F. S.; Oliveira, Daniel V.; Silva, Rui André Martins da
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /11/2012 ENG
Relevância na Pesquisa
66.95%
This paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-earth construction. Different liquid:solid ratios, alkali concentrations and Na2O : ash ratios were tested. Effect of calcium hidroxide, sodium chloride and concrete superplasticiser is also reported. Compressive strength up to 7 days at 60ºC was determined. Results show that, in terms of mechanical strength, there is an optimum value for the activator:solids ratio and the alkali concentration, and that a decrease in the Na2O:ash ratio results in strength increase. No improvement was observed with the sodium chloride or the superplasticiser, while the calcium produced only a short term increase in strength. SEM/EDS analysis were used to analyse microstructural development, showing that strength is fairly related to the Si:Al and Na:Si ratios.

Rammed earth : feasibility of a global concept applied locally

Silva, Rui André Martins da; Oliveira, Daniel V.; Miranda, Tiago F. S.; Escobar, Maria C.; Cristelo, Nuno
Fonte: Sociedade Portuguesa de Geotecnia Publicador: Sociedade Portuguesa de Geotecnia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2012 ENG
Relevância na Pesquisa
67.39%
Rammed earth is an ancient building technique that has been continuously reinvented in the dynamic movement of people all over the world, where it has been used to build from dwellings to enormous fortresses and city walls. In the particular case of Portugal, the inhabitants have been closely related to earth construction. From one region to another, rammed earth, adobe and wattle-and-daub buildings are frequently found. The rammed earth construction is mainly found in the southern part of Portugal and is almost absent from the north. However, the relatively low seismic hazard of the north of Portugal plus the sustainability of earth as a building material encourages the development of this technique in the region. The suitability of the typical granite residual soils from the Minho region for rammed earth construction was assessed by means of an experimental program, in which three representative soils were subjected to expeditious and laboratory tests that evaluated the characteristics of the soils and the performance of rammed earth built with them. The results showed that the granite residual soils tested fulfil most of the requirements needed for rammed earth construction, being the low compressive strength its main limitation. In this way...

Residual granitic soil improvement for rammed earth construction

Cristelo, R.; Roma, R.; Fernandes, L.; Miranda, Tiago F. S.; Oliveira, Daniel V.; Silva, Rui André Martins da
Fonte: Sociedade Portuguesa de Geotecnia Publicador: Sociedade Portuguesa de Geotecnia
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2012 ENG
Relevância na Pesquisa
67.1%
This paper describes the research developed to evaluate the performance of stabilised residual granitic soil from the north region of Portugal. It is part of a research project designed to investigate the possibility of using this soil for rammed earth construction. Since its reduced plasticity makes the use of lime less effective, and the increasing environmental concerns with cement production can no longer be ignored, the study was focused on binders made from alkaline activation of low calcium fly ash. Therefore, the aim of this work was to determine, through a parametric analysis using laboratory tests, the optimum fly ash – based alkaline activated binder for improving granitic soil, in terms of mechanical strength. Identification of the key parameters allowed the characterisation of the most effective mixtures, which will be later used in the construction of large rammed earth wall panels that will be tested according to proper specifications.

Rammed earth construction with granitic residual soils : the case study of northern Portugal

Silva, Rui André Martins da; Oliveira, Daniel V.; Miranda, Tiago F. S.; Cristelo, Nuno; Escobar, Maria C.; Soares, Edgar
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
67.2%
Building in unstabilised rammed earth results in low environmental impact. However, northern Portugal has not historical tradition with this technique, and thus the suitability of the local granitic residual soils is unknown. This paper presents an experimental investigation, where this possibility is assessed. The results showed that these soils are unsuitable, and that rammed earth construction is only feasible if these soils go through a stabilising process. The alkaline activation of fly ash was investigated as an environmentally friendly stabilisation technique, and it proved to be capable of improving the performance of rammed earth.

Modelling of rammed earth under shear loading

Silva, Rui André Martins da; Oliveira, Daniel V.; Micolli, L.; Schueremans, Luc
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 14/10/2014 ENG
Relevância na Pesquisa
67.42%
The intensive use of earth as a building material since ancient times resulted in an important and significant earthen built heritage currently existing worldwide spread. The rammed earth technique has a significant presence in this heritage, where it served to build from simple dwell-ings to fortresses. However, the high vulnerability of rammed earth constructions to decay agents and to seismic events puts in risk their further existence and the lives of millions of peo-ple. With respect to the seismic behaviour of rammed earth walls, the understanding and mod-elling of their shear behaviour are topics underdeveloped in the bibliography. Nevertheless, these topics are of extreme importance in the preservation and strengthening of rammed earth constructions. Therefore, this paper presents a numerical work aiming at modelling the non-linear behaviour of unstabilised rammed earth under shear loading, resorting to the finite ele-ments method (FEM). The models were used to simulate the behaviour of a set of rammed earth wallets tested under diagonal compression. Both macro- and micro-modelling approach-es were considered, where the objective of this last approach was to evaluate the influence of apparent weakness of the interfaces between layers on the shear behaviour. The total strain ro-tating crack model (TSCRM) was used to simulate the behaviour of the rammed earth material...

Modelling of the structural behaviour of rammed earth components

Silva, Rui André Martins da; Oliveira, Daniel V.; Schueremans, Luc; Lourenço, Paulo B.; Miranda, Tiago F. S.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 02/09/2014 ENG
Relevância na Pesquisa
67.33%
The rammed earth technique has a significant presence in the earthen built heritage, where it served to build from simple dwellings to fortresses. However, the high vulnerability of rammed earth constructions to decay agents and to seismic events puts at risk their further existence and the lives of millions of people. With respect to the seismic behaviour of rammed earth walls, the understanding and modelling of their shear behaviour are topics rarely approached in literature. Nevertheless, these topics are of extreme importance in the preservation and strengthening of rammed earth constructions. This paper presents an experimental and numerical work where the shear behaviour of unstabilised rammed earth (URE) is analysed. The experimental program consisted in the testing of several URE wallets under diagonal compression, which allowed a better understanding of the shear behaviour of URE. The numerical work consisted in the modelling of the previous tests by the finite element method and by considering both the macro- and micro-modelling approaches. In general, the numerical models showed a good agreement with the experimental results.; Fundação para a Ciência e a Tecnologia (FCT)

Shear behaviour of rammed earth walls repaired by means of grouting

Silva, Rui André Martins da; Oliveira, Daniel V.; Schueremans, Luc; Miranda, Tiago F. S.; Machado, Júlio
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 07/07/2014 ENG
Relevância na Pesquisa
66.95%
Southern Portugal presents a rich heritage constituted by several constructions made from unstabilised rammed earth (URE), which are threatened by several factors, ranging from lack of conservation to a non-negligible seismic hazard. These threatens are enhanced by the fact that little is known about the shear behaviour of URE constructions. The preservation of this heritage requires definitely the development of this knowledge and, in addition, the development of adequate intervention solutions. This paper presents an experimental program where the shear behaviour of URE is assessed by means of diagonal compression tests on representative wallet-specimens. Furthermore, the use of mud grouts in repairing cracks was also assessed. The results showed that the shear behaviour of URE depends on the binding capacity promoted by the clay fraction and on the friction and interlocking promoted by the coarse aggregates. The repair by injection was shown to promote satisfactory shear strength recovery of the specimens, but was less effective in recovering the initial shear stiffness.; Fundação para a Ciência e a Tecnologia (FCT)

Repair of rammed earth by injection of mud grouts : a case study from Portugal

Silva, Rui André Martins da; Oliveira, Daniel V.; Schueremans, Luc; Lourenço, Paulo B.; Miranda, Tiago F. S.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 07/05/2014 ENG
Relevância na Pesquisa
67.27%
The region of Alentejo, in southern Portugal, holds an important heritage built in rammed earth. However, little is known about this heritage, which is often found in a relative advanced level of decay. The presence of cracks is a common damage and is responsible for debilitating the structural performance of these constructions, putting in risk their existence and the life of thousand of people. However, the preservation and conservations of this rammed earth heritage requires adopting compatible intervention solutions. With this respect, the repair of cracks by means of the injection of mud grouts is a technique that has been showing great potential. Thus, this paper aims at contributing for the development of the knowledge on the rammed earth heritage from Alentejo and of the injection of mud grouts. With this purpose, an experimental program was carried out where the suitability of soils from Alentejo for unstabilised rammed earth was assessed, as well as the repair effectiveness of the injection of mud grouts.; Fundação para a Ciência e a Tecnologia (FCT)

Improving thermal performance of rammed earth walls using expanded clay aggregate

Correia-da-Silva, José; Pereira, João
Fonte: Universität Graz Publicador: Universität Graz
Tipo: Aula
ENG
Relevância na Pesquisa
67.38%
The use of earth as a building material dates back to the beginning of our civilization. In the South of Portugal there is still a large number of buildings with rammed earth walls, but this technology has been falling into disuse since the middle of last century. The earth construction is highly sustainable since earth is a local material and is 100% reusable. The buildings with rammed earth walls have a high thermal inertia which, given the climate characteristics Portugal, improves its thermal behaviour. However, it is desirable that the thermal conductivity of the rammed earth were lower. Environmental concerns related to energy consumption associated with comfort in housing and construction, transportation and application of materials used in construction, has led us to seek new solutions in building typologies on earth. Considering these aspects and improving the energy efficiency in buildings, this paper presents the results of tests performed in the laboratory on building new solutions on earth. Geotechnical characterization of the soil used was made and various compositions prepared with the incorporation of expanded clay. The expanded clay was chosen as a thermal insulator made from raw materials available in the regions of Alentejo and Algarve (South of Portugal)...

Improving Thermal Performance of Rammed Earth Walls Using Expanded Granulated Cork

Correia-da-Silva, J. J.; Pereira, João
Fonte: Solar Energy and Building Physics Laboratory (LESO-PB) Ecole Polytechnique Fédérale de Lausanne (EPFL) Publicador: Solar Energy and Building Physics Laboratory (LESO-PB) Ecole Polytechnique Fédérale de Lausanne (EPFL)
Tipo: Aula
ENG
Relevância na Pesquisa
67.37%
The use of soil construction dates back to the beginning of our civilization. In the South of Portugal there is still a large number of buildings with rammed earth walls, but this technology has been falling into disuse since the middle of last century. The earth construction is highly sustainable since earth is a local material and is 100% reusable. The buildings with rammed earth walls have a high thermal inertia which, given the climate characteristics Portugal, enjoys its thermal behavior. However, it is desirable that the thermal conductivity of the rammed earth were lower. Environmental concerns related to energy consumption associated with comfort in housing and construction, transportation and application of materials used in construction, has led us to seek new solutions in building typologies on earth. Considering these aspects and aiming to improve the energy efficiency in buildings with rammed earth walls, this paper presents the results of tests performed in laboratory to characterize phisical properties of several compositions containing soil and expanded granulated cork. Compositions were considered soil and expanded granulated cork having the following percentages of expanded granulated cork, 0%, 10%, 15%, 20% and 25%. In order to characterize the different compositions from the point of view of mechanical and thermal performance...

Improving rammed earth wall thermal performance with added expanded granulated cork

Correia-da-Silva, J.J.; Pereira, João; Sirgado, Jorge
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
67.37%
Most construction materials require large amounts of energy for production and transportation purposes and are also asso- ciated with high levels of greenhouse gas emissions. One such material, rammed earth, has the advantage of being reusable and extremely durable, while it can also be locally sourced. However, rammed earth walls have a low thermal resistance. The aim of this study is to improve the thermal performance of rammed earth walls by increasing their thermal resistance. To this end, a range of different percentages and particle sizes of expanded granulated cork were added to rammed earth samples. The thermal conductivity of the samples was then determined in the laboratory and the data obtained were used to calculate heat transfer coefficients for a model rammed earth wall. Finally, the samples were subjected to uniaxial compression tests to determine whether the added cork led to a reduction in compressive strength. It was found that adding 10% granulated cork produced a reduction of about 12% in the heat transfer coefficient of a rammed earth wall with a thickness of 0.60 m, while the 28% reduction in compressive strength recorded is within the limits set out in the relevant standards.

Repair mortars for rammed earth constructions

Faria, Paulina; Gomes, Maria Idália
Fonte: FEUP Publicador: FEUP
Tipo: Conferência ou Objeto de Conferência
Publicado em /03/2011 ENG
Relevância na Pesquisa
67.34%
Proceedingsof the XII DBMC – 12th International Conference on Durability of Building Materials and Components, Vol.2, Porto, FEUP, March 2011, p.689-696; Rammed earth buildings, with resistant and monolithic walls, often have constructive pathology. A survey on more than thirty rammed earth buildings, mainly in Alentejo region (South Portugal), was conducted. As a result, it was found that surface deterioration of the walls seemed to be an usual problem. Many rammed earth buildings are deteriorating due to lack of maintenance and rehabilitation, but also due to incorrect repairs. Several of them were repaired by applying cement-based mortars in the attempt to overcome the general decay, of the walls that could or not be deep. This paper presents the most common pathology: problems due to water ingress and low drying capacity; salt transport and contamination; construction technology like voids left from the formworks; biological attack; different mechanical behaviour between the walls and the repair mortars - mechanical incompatibility. An intervention methodology for repair the degradation of exterior surface, including anomalies diagnosis and application of these repair mortars, is proposed. The support samples preparation - laboratorial rammed earth blocks with surface deterioration - is also described. Finally...

The monitoring of rammed earth experimental walls and characterization of rammed earth samples

Faria, Paulina; Silva, Vitor; Pereira, C.; Rocha, M.
Fonte: Taylor & Francis Group Publicador: Taylor & Francis Group
Tipo: Conferência ou Objeto de Conferência
Publicado em /06/2012 ENG
Relevância na Pesquisa
67.27%
RESTAPIA 2012 - Int. Conf. on Rammed Earth Conservation, Valencia, 21-23 June 2012; This article analyzes differences recorded in the construction and ageing of experimental rammed earth walls. After 10-12 years of exposure some superficial degradation was observed in some walls, pointing to the necessity of applying a compatible surface protection. The behavior of samples of the rammed earth similar to those used in the walls is also analyzed in terms of density, thermal conductivity, capillary ab-sorption and drying. A different behavior was recorded between: different unstabilized soils, the same soil but with different grading, the same soil but stabilized with different hydraulic binders and different soils stabi-lized with the same binder.

The compatibility of earth-based repair mortars with rammed earth substrates

Gomes, M. Idália; Gonçalves, Teresa D.; Faria, Paulina
Fonte: Historic Mortars Conference Publicador: Historic Mortars Conference
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2013 ENG
Relevância na Pesquisa
67.42%
3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, Scotland; Earth constructions are susceptible to degradation due to natural or human causes. The degradation of the exterior surface of earth walls is very common, either due to lack of maintenance or to the use of incompatible materials, and often requires the application of a repair mortar. This work analyses experimentally the performance of earth-based repair mortars applied on rammed earth surfaces. The mortars are based on earth collected from rammed earth buildings in south Portugal or on a commercial earth. Eight repair mortars were formulated, with the unstabilized soils or including also small binder content. Four types of binder were tested: hydrated air-lime, natural hydraulic lime, Portland cement and natural cement. The repair mortars were applied on two types of standard defects purposely made on rammed earth blocks, representing the most currently defects found on exterior rammed earth surfaces: standard superficial defect and standard deep defect. The performance of the mortars, their compatibility with the substrates and the visual effectiveness of the intervention were evaluated. It was concluded that the mortars behaved differently when applied on different rammed earth supports. However...

Unstabilised rammed earth: characterization of material collected from old constructions in South Portugal and comparison to normative requirements

Gomes, M. Idália; Gonçalves, Teresa D.; Faria, Paulina
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
Relevância na Pesquisa
67.22%
International Journal of Architectural Heritage, 8: 185–212, 2014; Unstabilized rammed earth is a recyclable, economical, and eco-friendly building material, used in the past and still applied today. Traditionally, its use was based on a long empirical knowledge of the local materials. Because this knowledge was mostly lost or is no longer sufficient, in many countries normative documents have been produced to allow the assessment of rammed earth soils.With the aim of contributing for a refining of these normative requirements, this article presents a research work that included: (i) collection of Unstabilized rammed earth samples from six constructions in Portugal; (ii) a literature survey of normative and complementary documents to identify the most mentioned key-properties, the test procedures and the corresponding threshold limits; and (iii) a discussion of the test procedures and of the thresholds limits in the light of the experimental results. The analyzed properties are the particle size distribution, maximum particle size, plasticity, compaction, linear shrinkage, organic content, and salt content. The work highlights the advantages of taking into account the characteristics of existing constructions as a basis for the establishment and further refining of consistent threshold values. In particular...

Seismic rehabilitation of sixteenth-and seventeenth-century rammed earth-built chueches in the andean highlands: field and laboratory study; Journal of performance of constructed facilities

López Pérez, Cecilia; Ruiz Valencia, Daniel; Unigarro, Stefanía; Dominguez, María Teresa
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 04014144-1 / 04014144-17
Relevância na Pesquisa
67.22%
28; In a Latin American context, few studies exist regarding the construction of churches during the colonial period using adobe and rammed-earth techniques. Investigations of their spatial characteristics, systems of construction, and structural behavior, therefore, are also scarce. This lack of research has led to poor results in restoration attempts for these kinds of churches, which has caused the loss of important Colombian architectural and historical heritage. Additionally, Colombia is at a high seismic risk, and adobe and rammed-earth buildings are particularly vulnerable during earthquakes. This paper presents the results of an investigation of these kinds of structures, developed by the investigative groups investigation group on materials and structures (GRIME) and Estructuras & Construcción (at Pontificia Universidad Javeriana) during the period 2002–2013. The investigation focuses on churches in the geographical area within the central Colombian highlands built during the 16th and 17th centuries. The study takes an architectural and historical approach coupled with structural laboratory work (involving shake table tests on 1:50 models), where the authors applied a reinforcement alternative with confinement wood elements to improve the seismic performance of the structural system of rammed-earth churches. According to these results...

Thermal and structural performances of insulated cavity rammed earth wall houses.

Dong, Xiang
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2015
Relevância na Pesquisa
67.2%
Rammed earth (RE) wall construction is perceived to carry extremely low embodied energy and have desirable thermal performance without much energy input for heating and cooling due to the thermal mass effect. In Australia, however, because of the low thermal resistance (R-value) of RE material, it is very difficult for houses constructed with only solid RE walls to comply with the Deemed-to-Satisfy Provision provided in the National Construction Code (NCC) by the Building Code of Australia, which specifies the minimum R-value for external walls. The NCC provides an alternative provision, named the Energy Efficiency Provision, which states a maximum allowance of energy use by a residential house. As houses have the potential to consume little energy load particularly when passive design strategies are implemented, houses built with RE walls may still be able to comply with the Energy Efficiency Provision of the NCC. Adding thermal insulation to the wall construction is one way to ensure that RE wall houses comply with NCC. Normally, rigid board foam insulation can be inserted in the middle of RE walls to maintain the aesthetics of the wall surfaces and part of the thermal mass effect. The result of this solution is an insulated cavity rammed earth (ICRE) wall system. This solution...

Feasibility of rammed earth constructions for seismic loads in Australia

Dong, X.; Griffith, M.; Soebarto, V.I.
Fonte: Engineering Australia Publicador: Engineering Australia
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
66.95%
Out-of-plane bending tests were conducted to determine whether rammed earth (RE) walls, designed to satisfy the thermal performance requirements specified by the Building Code of Australia, will satisfy the seismic loading requirements. A 2.4 m tall by 1.2 m wide full-scale insulated RE wall comprised of two 175 mm thick leaves separated by a 50-mm thick layer of insulation, was tested and the results were compared to that of a solid 300-mm thick RE wall. Both walls remained stable after cracking up to displacement of 50 mm (over 20% of wall thickness). The acceleration necessary to generate the initial forces to cause cracking was over 0.77 g, well in excess of the maximum design accelerations for face-loaded masonry walls in Australia. Furthermore, it was found that the flexural strength of the insulated cavity RE wall was simply the sum of the flexural strengths of the two leaves and that both walls after reaching their peak strength and cracking at mid-height responded as two rigid rocking blocks.; Xiang Dong, Michael Griffith and Veronica Soebarto

Seismic behaviour of portuguese rammed earth buildings

Barros, Ricardo Freitas Lima da Silva; Varum, Humberto; Rodrigues, Hugo; Correia, Mariana; Vasconcelos, Graça; Lourenço, Paulo B.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2015 ENG
Relevância na Pesquisa
67.2%
Rammed earth is one of the oldest building materials in the world and is present in the Portugal with a particular focus in the South of the country. The mechanical properties and the structural behaviour of rammed earth constructions have been the subject of study of many researchers in the recent years. This study is part of a broader research on vernacular seismic culture in Portugal. Numerical analyses were carried out on a rammed earth masonry construction representative of the vernacular heritage of Alentejo region. Variations in the geometry, constructive characteristics and material properties were implemented and the main conclusions of the non-linear static and modal analysis are presented. Analysing the damage framework allowed interpreting the weaknesses of this type of constructions and consider the most appropriate reinforcement methodologies.