Finalmente chegou aquilo de que precisávamos para dar credibilidade em Portugal à construção com terra...um rigoroso estudo de investigadores de uma Universidade Americana!
Uff, estamos salvos!...Qual crise!? Agora sim... damos a volta a isto...
Em seguida aqui fica a reportagem sobre o estudo apresentado.
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"A new research has determined that the secret of a successful sandcastle could aid the revival of an ancient eco-friendly building technique.
The researchers, led by experts at Durham University’s School of Engineering, have carried out a study into the strength of rammed earth, which is growing in popularity as a sustainable building method.
Just as a sandcastle needs a little water to stand up, the Durham engineers found that the strength of rammed earth was heavily dependent on its water content.
Rammed earth is a manufactured material made up of sand, gravel and clay, which is moistened and then compacted between forms to build walls.
Sometimes, stabilizers such as cement are added but the Durham research focused on unstabilised materials.
The research showed that a major component of the strength of rammed earth was due to the small amount of water present.
Small cylindrical samples of rammed earth underwent “triaxial testing”, where external pressures are applied to model behavior of the material in a wall.
The researchers found that the suction created between soil particles at very low water contents was a source of strength in unstabilised rammed earth.
They showed that rammed earth walls left to dry after construction, in a suitable climate, could be expected to dry but not lose all their water.
The small amount of water remaining provided considerable strength over time.
According to the researchers, their work could have implications for the future design of buildings using rammed earth as the link between strength and water content becomes clearer.
There is increasing interest in using the technique as it may help reduce reliance on cement in building materials.
Rammed earth materials can usually also be sourced locally, thereby reducing transport needs.
As well as informing new build designs, the team hopes their findings could also aid the conservation of ancient rammed earth buildings by putting methods in place to protect against too much water entering a structure, which would reduce its strength.
According to research project leader, Dr Charles Augarde, of Durham University’s School of Engineering, “We know that rammed earth can stand the test of time, but the source of its strength has not been understood properly to date.”
“Our initial tests point to its main source of strength being linked to its water content,” he said.
“By understanding more about this, we can begin to look at the implications for using rammed earth as a green material in the design of new buildings and in the conservation of ancient buildings that were constructed using the technique,” he added. (ANI)"
The researchers, led by experts at Durham University’s School of Engineering, have carried out a study into the strength of rammed earth, which is growing in popularity as a sustainable building method.
Just as a sandcastle needs a little water to stand up, the Durham engineers found that the strength of rammed earth was heavily dependent on its water content.
Rammed earth is a manufactured material made up of sand, gravel and clay, which is moistened and then compacted between forms to build walls.
Sometimes, stabilizers such as cement are added but the Durham research focused on unstabilised materials.
The research showed that a major component of the strength of rammed earth was due to the small amount of water present.
Small cylindrical samples of rammed earth underwent “triaxial testing”, where external pressures are applied to model behavior of the material in a wall.
The researchers found that the suction created between soil particles at very low water contents was a source of strength in unstabilised rammed earth.
They showed that rammed earth walls left to dry after construction, in a suitable climate, could be expected to dry but not lose all their water.
The small amount of water remaining provided considerable strength over time.
According to the researchers, their work could have implications for the future design of buildings using rammed earth as the link between strength and water content becomes clearer.
There is increasing interest in using the technique as it may help reduce reliance on cement in building materials.
Rammed earth materials can usually also be sourced locally, thereby reducing transport needs.
As well as informing new build designs, the team hopes their findings could also aid the conservation of ancient rammed earth buildings by putting methods in place to protect against too much water entering a structure, which would reduce its strength.
According to research project leader, Dr Charles Augarde, of Durham University’s School of Engineering, “We know that rammed earth can stand the test of time, but the source of its strength has not been understood properly to date.”
“Our initial tests point to its main source of strength being linked to its water content,” he said.
“By understanding more about this, we can begin to look at the implications for using rammed earth as a green material in the design of new buildings and in the conservation of ancient buildings that were constructed using the technique,” he added. (ANI)"
Brincadeiras à parte, embora algumas das conclusões apresentadas sejam interessantes, e desmistifiquem alguns preconceitos, o estudo demonstra sobretudo como os americanos (alguns...é bom não generalizar) caiem facilmente em lugares comuns nestas coisas da construção com terra, e tudo nos é vendido como descobertas revolucionárias !
Oh senhores, saiam mas é do laboratório, vistam lá o calçanito, o téninho e a meínha branca, e visitem países como o Mali, Marrocos, o Yémen ou aqui o Sul de Portugal (reparem como aproveitamos e promovemos o Turismo nacional!) e deixem-se de tretas! Parem lá de inventar a roda!
aqui fica o link para a fonte
![Terra [In]cognita project: Earthen architecture in Europe](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIS5lNr8tO_b1BIAUxQ7yOk-fWtBc-FOHi46AK7z5ExhggwlbKr1PYY6WxDega-Jey3Gc5tVPqpfmw8v-uiG8VWsXYWoBV7mPNsTfnEZ9HICEYXZwTmBQT1fbxZ0D0nR5b153SjGCFhk4/s285/logoterraincognita.jpg)
2 comentários:
Olá Pedro. A minha opinião neste caso difere um pouco da tua. Concordo, obviamente, que a experiência do terreno é fundamental para o entendimento do que é o material terra, as técnicas construtivas, etc. Muitas vezes é este saber de experiência feito que fornece respostas que um microscópio não pode de forma alguma responder.
No entanto, parece-me também fundamental referir a importância destes estudos como forma de conferir credibilidade a este material. Aquilo que muitos sabem, por senso comum, se não for provado cientificamente pode não se revelar suficiente quando está em causa a competição com outros materiais de construção que foram já submetidos a testes intensivos e cujos comportamentos estão previstos. Bem sei que noutros tempos estes pormenores eram pouco importantes, no entanto, e porque esta é a forma como a sociedade evoluiu (e agrada-me pensar que estamos de facto a evoluir enquanto seres humanos) estes pormenores podem fazer toda a diferença na altura de fazer a escolha.
Não esqueçamos por isso que é graças à investigação que se atribuem “números” a “sensações” tornando, neste caso, as características do material mensuráveis. E, na minha humilde opinião, tal facto em muito pode contribuir para o abandono do preconceito que ainda se encontra tantas vezes associado à construção em terra.
Acredito que a maioria das pessoas envolvidas nestes trabalhos, já tenha feito esse exercício de visitar os países que referes. Talvez até tenha sido isso que os fez investigar a terra… A verdade é que se deve também ao trabalho dos investigadores espalhados pelos quatro cantos do mundo a difusão da construção em terra, e tal facto não se pode ignorar.
Termino reforçando o que escrevi no início, a experiência no terreno é fundamental, no entanto sou da opinião que as duas áreas (a teoria e a prática) se complementam e que ambas ocupam um merecido lugar no mundo da arquitectura de terra.
(perdoa-me o longo texto)
Oi Célia, não deixamos de concordar, a teoria e a prática são irmãs complementares do saber, sou mesmo da opinião que a credibilidade da terra tem crescido fruto também do trabalho fantástico de investigadores apaixonados. Não me expliquei, quando me refiro em tom um pouco crítico a estes estudos americanos(e não o faço directamente a nenhum em particular), não acuso ninguém de não ir ao terreno, faço a provocação mais como uma análise ao modo reverencial e cego como infelizmente em Portugal se olha para este tipo de investigação, deixando a ideia de que primeiro "Ha isso não presta!" sem pensar e de repente "...ha os americanos dizem que é bom?!, epá então..." esquecendo-se as pessoas de pensarem pela sua cabeça e olharem mais vezes para a prática real da construção em terra.
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