No site da RTP aqui, também é possível ver uma reportagem sobre o mesmo tema.
Nuninho! Obrigado pela dica!
Sexta-feira, 27 de Fevereiro de 2009
Quarta-feira, 25 de Fevereiro de 2009
Terça-feira, 24 de Fevereiro de 2009
SEMINARIO IBEROAMERICANO DE CONSTRUCCIÓN CON TIERRA
SEMINARIO ARGENTINO DE ARQUITECTURA Y CONSTRUCCION CON TIERRA
CRIATiC - FAU / UNT Avda. Roca 1800. San Miguel de Tucumán, Argentina
Prof. Arq. Rafael F. Mellace - Director del CRIATiC
Dra. Arqta. Silvia Cirvini - Directora INCIHUSA
Agencia Nacional de Promoción Científica y Tecnológica (ANPCYT)
Ministerio de Ciencia, Tecnología e Innovación Productiva / Presidencia de la Nación
Ambos Seminarios apuntan a un doble objetivo: por una parte, reunir a los científicos, tecnólogos y profesionales que trabajan en torno al tema para analizar, desde el pasado hacia el presente, tanto lo referente al patrimonio cultural, como al estado actual de la tecnología de construcción con tierra. Por otra, habilitar un espacio de discusión que permita examinar el desarrollo de los programas y proyectos en marcha, evaluando posibles resultados hacia futuro.
En tal sentido, las acciones fundamentales se dirigen a actualizar, registrar, discutir y difundir los avances producidos en las investigaciones tecnológicas y las innovaciones propuestas para el diseño, la producción y la conservación de la arquitectura de tierra en diversos contextos regionales. Al mismo tiempo, estimular el intercambio de experiencias, fortalecer las relaciones técnico-científicas entre organismos, centros de investigación y profesionales de Iberoamérica vinculados a la disciplina y trazar los lineamientos de posibles programas que puedan implementarse en el futuro.
Los Seminarios están dirigidos a profesionales arquitectos, ingenieros civiles y constructores, ambientalistas, geólogos, antropólogos; a maestros de obra, artesanos, técnicos y estudiantes de cualquiera de estas disciplinas.
A fin de permitir una evaluación general del campo del saber y práctica del arte, las conferencias, ponencias de base, comunicaciones, pósters o exposición de trabajos se encuadrarán en las siguientes áreas temáticas:
II_Arquitectura de tierra y medio ambiente: Creatividad y sustentabilidad
III_Investigación y desarrollo tecnológico: Materiales, componentes, sistemas y procesos constructivos. Resistencia y durabilidad / Sismo y humedad
IV_Patrimonio edilicio: Inventario. Intervención. Preservación / restauración. Patrimonio turístico, gestión y gerenciamiento. Difusión
V_Normalización: Estado de la cuestión. Normas y recomendaciones técnicas. Alcances y ámbitos de aplicación
VI_Proyectos ejemplares: Diseño, construcción y mantenimiento. Vivienda social, individual. Prototipos y transferencia
VII_Educación, Formación y Capacitación: Recursos humanos, profesionales, técnicos y artesanales
UNT - Universidad Nacional de Tucumán
FAU - Facultad de Arquitectura y Urbanismo
SIDETEC - Secretaria de Estado de Innovación y Desarrollo Tecnológico de Tucumán
CRICYT- Centro Regional de Investigaciones Científicas y Tecnológicas, Mendoza
PROTIERRA - Red Argentina de Promoción y Difusión de la Arquitectura de tierra. Tucumán
PROTERRA - Red Iberoamericana de Arquitectura y Construcción con Tierra. México DF
_Guerrero Baca, Luis Fernando
Doctor Arquitecto, UAM, Azcapotzalco, México. Máster en Arquitectura, Restauración de Monumentos. ENCRyM – INAH
_Cirvini, Silvia Augusta
Architecte DPLG, Maître STA, Ecole d'Architecture de Grenoble. Directeur scientifique du Laboratoire de recherche CRATerre-EAG ; Responsable de la Chaire UNESCO Architecture de terre, Cultures Constructives et Développement Durable
Arquitecto UNMP. Máster CEAA-terre, Esc. Arquitectura de Grenoble, Francia; Investigador científico CONICET. Instituto de Arte Americano, (FADU/UBA)
_Martins Neves, Celia
Ing. Civil, Mestre em Engenharia Ambiental Urbana. Pesquisadora do CEPED - Centro de Pesquisas e Desenvolvimento; Universidade do Estado da Bahia.
Ingeniero. UTN. Máster Metodología de la Investigación Científica, UNER; Especialista Control de Vectores, y Agentes en la Vivienda, Organización Panamericana de la Salud.
Doctora Arquitecta, UNT. Profesora Titular Historia de la Arquitectura y Profesora Magister en Historia de la Arquitectura y el Urbanismo Latinoamericanos, FAU/UNT
Arquitecto, UNT; Máster (Candid.) UBB-Chile. Profesor Titular Disciplina Construcciones. Director Académico CRIATiC, FAU/UNT
_Arqta. Stella Maris Latina
_Arqta. Mirta Eufemia Sosa
_Inga. Lucía Elizabeth Arias
_Arqta. Irene Cecilia Ferreyra
_Ing. Carlos Eduardo Alderete
_Dra. Silvia Augusta Cirvini
_Arq. Rafael Francisco Mellace
Se podrá participar en este evento en calidad de ponente, expositor o asistente. La presentación de trabajos -ponencias, comunicaciones, póster o afiches- deberán ser inéditos y encuadrarse en alguna de las citada áreas temáticas.
Ponencias / comunicaciones
Se enviarán resúmenes en archivo tipo MS Word, con una extensión de 250 palabras como mínimo y 500 como máximo. Formato A4, con márgenes, superior 3cm.; izquierdo 3cm.; derecho e inferior 2,5cm.
Fuente Arial 11; texto sin sangría, a un espacio y medio.
_Título del trabajo: mayúsculas y negrita
_Nombre del autor o de los autores: tipo título y negrita
_Institución que representa: tipo oración, sin negrita.
_Dirección electrónica, teléfono y fax. (ídem anterior)
_Área temática en que se encuadra la comunicación. (ídem anterior)
_Palabras clave: hasta cuatro, tipo título y negrita
A pie de página se incluirá un breve currículum del autor / autores en un máximo de 5 renglones.
Pósters / afiches
Para la presentación de pósters se enviará un breve resúmen (hasta 250 palabras) en archivo tipo MS Word. Formato A4, con márgenes, superior 3cm.; izquierdo 3cm.; derecho e inferior 2,5cm.
Fuente Arial 11; texto sin sangría, a un espacio y medio, donde constará:
_Título del trabajo
_Autor/es. A pie de página incluirá un breve currículum del o de los autores con un máximo de 5 renglones
_Institución que representa. Dirección electrónica, teléfono y fax
_Área temática en que se encuadra
_Palabras clave: 3 en normal y tipo título
Recepción de trabajos
Ponencias / comunicaciones
La fecha límite para la recepción de los resúmenes será el 7 de marzo de 2009
Los trabajos in extenso (cuyos resúmenes hayan sido aceptados) se recibirán hasta el 25 de abril de 2009
Pósters / afiches
La fecha límite para la recepción de los resúmenes de afiches será el 25 de abril de 2009
Los pósters o afiches impresos (cuyos resúmenes hayan sido aceptados) se recibirán hasta el 30 de mayo de 2009
A los fines de la presentación de trabajos -ponencias, comunicaciones, póster o afiches- seran oficiales de estos encuentros, los idiomas castellano y portugués
Av. Roca Nº 1800 - CP 4000 - San Miguel de Tucumán, Argentina
Tel 54 381 436 4093 (int 7919/7912) Fax 54 381 436 4141
Correo electrónico firstname.lastname@example.org
Sitio web: www.criatic.com.ar
Segunda-feira, 23 de Fevereiro de 2009
Rammed earth is going mainstream as a result of its insulation and sustainability
There's no shortage of smart technology for architects keen on low-energy design. Glasscovered
Trombe walls, brises soleils and innumerable permutations of highly insulated curtain wall are today's mainstream technology. But how much of this innovation is just a solution looking for a problem? Are complex multi-layered building envelopes really more effective at temperature and energy control than a basic mud hut?
Proponents of rammed wall construction would argue the toss. They would point out that earth is free, earth is plentiful, and when compressed it has excellent thermal and acoustic insulation properties. All one has to do is excavate the soil, add a chemical stabiliser such as lime or sugar paste, compact the earth between wooden formers, and hey presto, you have a durable, strong and highly insulated wall.
The build process is simplicity itself. The selected soil is mixed to the right consistency, then compacted in layers using hand tools. Formers are used to act as a mould for thewall. Other materials can be added to improve compaction, such as ground glass, shredded rubber tyres or natural fibres. Once the wall has been constructed, the formers can be removed. The wall is immediately ready to take structural loads. Rammed earth walls used as internal partitioning can also suppress noise transfer between rooms very effectively. At the Eden Centre in Cornwall, the walls of the visitors' centre were built from earth excavated on site. The soil was compacted by hand to form 40 panels, each 2.5m high and weighing around 10 tonnes. The walls were strong enough to support themselves without reinforcement on the day they were built, and to support the roof loads of the centre. But while it's not surprising to find rammed earth walls at beacons of sustainability such as the Eden Project, the technology is also turning mainstream. Newcastle based architect Jane Darbyshire & David Kendall (JDDK) has designed Europe's largest internal rammed earth wall for the Rivergreen Business Centre at Aykley Heads in Durham.
Interestingly, the decision to create a rammed earth wall in the Aykley Heads project was driven by the client, Rivergreen Developments. The company had seen an earth wall at the Autonomous Environmental Information Centre (AtEIC) project at the Centre for Alternative Technology in Powys, and was keen to try the technique as part of its commitment to sustainable construction.
"We visited the AtEIC project with the client and were very impressed with the thermal and aesthetic qualities of the rammed earth wall," said JDDK's project architect Ruth Walters. "Although we didn't have any experience with the technology, the client was willing to take the risk. We also worked with consultants experienced in designing and building rammed earth walls."
The 6m-high, 600mm-thick rammed earth wall brings environmental benefits, because it uses natural materials readily available on site; and performance benefits because it offers a relatively cheap and simple method of creating a high thermal mass within the building to even out swings in temperature. It is also believed to help control moisture in the building.
The wall has been constructed in six separate panels inside the atrium of the 3,700sq m, two-storey, timber-framed building. Being south-facing and subject to direct solar gain, the wall absorbs the sun's energy during the day and releases it at night and early morning to preheat the adjacent offices prior to occupation.
The rammed earth wall is the most innovative of the building's sustainable features, which include space heating provided by a biomass boiler fed with wood pellets, and collecting rainwater for toilet flushing and irrigating the building's sedum roof. These helped it achieve an "excellent" Breeam rating. Approximately 80% of the material used in the wall's construction is fine sand obtained from the basement excavation. The remainder consists of gravels and clay from local quarries. The success of the method depends upon the proportions of the mix and the
overall moisture content, which will be unique to every wall.
Since there is no firing process and no toxic emissions, the amount of CO2 emitted depends solely on the transport requirements for additional materials, such as clay and chemical stabilisers. The Aykley Heads wall used 60% site material, with the remaining 40% transported in.
For the project, JDDK commissioned Bath University's Department of Architecture & Civil Engineering to develop the optimum blend of clay, sand and gravel and advise on improvements to the soil to improve compaction and cohesion. The team constructed sample panels to check stress resistance. JDDK's Walters feels this was a crucial step. "We would stress the importance of getting sample panels made and testing them for their aesthetics as well as their durability," she says.
Following its success at the Aykley Heads centre, JDDK Architects has since specified an external rammed earth wall for the £4.1 million Wild Bird Discovery Centre on Teesside. "The main risk is to do with controlling the shrinkage of the wall," says Walters. "At Aykley Heads we were able to build in a controlled environment - it's much easier to build internally. But we still made the wall in six separate panels, with expansion joints between them."
Other downsides of rammed earth construction include a lack of national guidelines for design and construction, higher labour costs for the compacting process, and limited data on the materials' physical characteristics. There is no shortage of guidelines for hot countries such as Australia, but very few in the UK.
The most recent guidance is a BRE book Rammed Earth: Design and Construction Guidelines published last year. It gives practical advice on the material selection, construction, design, detailing, maintenance and repair of rammed earth walls. JDDK relied heavily on Simmonds Mills, a Hereford-based firm which acted as the rammed earth consultant for the AtEIC project and led the team that constructed the walls. At Aykley Heads, it advised JDDK on soil types, shuttering and construction methods, and trained the construction operatives in earth-ramming techniques.
In common with many construction materials, the thermal performance of a rammed earth wall depends on its density, porosity and water content. Rammed earth walls between 1,400 and 1,800 kg/cu m can have thermal conductivity U-values of 0·7 to 0·9W/sqmK. As a comparison, the CIBSE Guide quotes thermal conductivity of 0·51W/sqmK at 1,400 kg and 0·87W/sqmK at 1,800 kg for homogenous masonry.
Allowing for normal internal and external surface resistances, and assuming the wall will be rendered and plastered, a nominal wall thickness of 2m may be needed to achieve a Uvalue of 0·35W/sqmK. Additional insulation is likely to be needed where rammed earth walls are used externally. Insulation would be best placed on the external elevation, leaving the internal spaces to take advantage of the wall's thermal mass.
Essentially, any finish that can be applied to brick or concrete can be applied to a rammed earth wall, such as tiling, rendering, lime washes, pebbly finishes or a clear coating of silicon emulsion to seal the earth. Environmentally friendly surface treatments include boiled vegetable extracts.
Undoubtedly rammed walls are a worthy contribution to sustainable architecture, but their use will not outweigh the energy used by conventional gas-fired heating or electrically powered ventilation. Architects seeking to reduce carbon dioxide emissions need to approach rammed earth walls as part of a wider strategy to reduce CO2 emissions. One thing they must not become is lipstick on the gorilla.
Aqui postamos os inúmeros filmes que encontramos na internet sobre construção com terra crua.
Basta seguir os links:
Construction en pisé au Maroc
La technique de batiment pisé au Maroc
Rammed Earth Construction from the Ground Up
Chapel of Reconciliation Berlin
Sassenroth & Reitermann: Chapel of Reconciliation, Berlin
Sassenroth & Reitermann Chapel of Reconciliation Berlin_1
FIRST EARTH (2/12) - Uncompromising Ecological Architecture
FIRST EARTH (7/12) - Uncompromising Ecological Architecture
Rammed earth in Hassilabied_Morocco
Sistema Construtivo COMTERRA - Barrocal
Visita a Aveiro - FILME 1_parte 1/3
Visita a Aveiro - FILME 1_parte 2/3
Visita a Aveiro - FILME 1_parte 3/3
Visita a Aveiro - FILME 2
Arquitetura de terra - taipa de pilão
Cob Earth Home_1_Saudi Arabia
Cob Earth Home_2_Saudi Arabia
Cob Earth Home_3_Saudi Arabia
Cob Earth Home_4_Saudi Arabia
Cob Earth Home_5_Saudi Arabia
Cob Earth Home_6_Saudi Arabia
Cob Earth Home_7_Saudi Arabia
Cob Earth Home_8_Saudi Arabia
Sábado, 21 de Fevereiro de 2009
Following the international expertise mission organized by the Association in New Gourna from 22 to 27 January 2009 an article entitled "Disaster in New Gourna" was published in the Magazine Akher Saa. You can view this article in the "News" page of our blog www.fathyheritage.com
The participants of the mission (International and Egyptian experts) observed a number of preoccupying problems in the village but were particularly alarmed by the construction of two administrative buildings which has begun two months ago just behind the Theatre. Egyptian authorities have been alerted and urged to implement conservatory measures.
An international Symposium organized by the Association will be held at the Bibliotheca Alexandrina (Alexandria, Egypt) on 30-31 May 2009. The Symposium will bring together Egyptian and international experts to discuss the future of the village of New Gourna and define the different possible scenarios for a sustainable conservation and restoration program.
Prior to the symposium, the issue of New Gourna will also be presented by Dr Leïla el-Wakil, President of the Association, during the first Mediterranean Conference on Earth architecture, Mediterra 2009, held in Cagliari (Sardinia, Italy) on 13-16 March 2009.
The Association thanks you once again for supporting and encouraging its endeavours
Leïla el-Wakil, President Rachida Teymour, Vice-President Nadia Radwan, Secretary
Quinta-feira, 19 de Fevereiro de 2009
A norma é a UNE 41410:2008
“Bloques de tierra comprimida para muros y tabiques. Definiciones, especificaciones y métodos de ensayo”
Esta é a primeira normativa espanhola não experimental de um Organismo de Regulamentação Europeia.
Após alguns anos de trabalho, o subcomité AEN/CTN 41 SC 10, da Asociación Española de Normalización (AENOR), entidade de regulamentação espanhol, responsável pela elaboração das normas espanholas (Normas UNE), semelhante a outros organismos europeus DIN (alemão) e o AFNOR (francês), elaborou e aprovou a Norma UNE 41410.
Ela foi criada, segundo a AENOR, pela necessidade de caracterizar o material, descrevê-lo e conhecer as propriedades da matéria-prima e os produtos associados, assim como os testes e ensaios necessários.
Um agradecimento especial a Ignacio Cañas pela informação e um recado aos legisladores Portugueses, num país que legisla tanto e sempre a reboque dos demais, está na hora de olhar para a construção com terra com o reconhecimento e a importância que ela merece.
Quarta-feira, 11 de Fevereiro de 2009
Moves to develop UK production of unfired clay bricks are driven by the growing demand for sustainable construction materials to displace conventional products. Tom Morton, Principal Architect at Arc, Fife, UK, examines the key factors in achieving a scale of use that would yield significant benefits, such as standardisation and low cost.
The main advantages of using unfired clay as a binder in building materials instead of cement, gypsum or fired clay are a healthy indoor environment and low environmental impact over the whole life cycle of the material.
These attributes have been well established over the last fifteen years in Germany, where a small specialist construction sector has experienced sustained growth through the development of national standards in using unfired clay and the use of sophisticated products in prestige projects.
But application in the UK has been hampered by the lack of guidance and standardisation in available materials and the expense of importing modern products from Germany. The development of best practice guidance and low cost materials manufacturing in the UK would remove significant barriers. Attention now focuses on ways to realise this shift in attitude.
Low impact manufacturing Unfired clays are natural materials with varying properties, commonly combined with fine aggregates and fibres to make a range of products such as bricks, blocks, boards, mortars and plasters. Clay materials produce very little waste, as there is no fundamental chemical change or ceramicisation involved in their manufacture and use. The materials are easily recycled or cleanly disposed of.
Although clay manufacture uses a finite resource, the environmental impact can be benign, with low value agricultural land being transformed into biodiverse wetland habitats.
Sources of clay are shallower and less remotely located than sources of gypsum and cement or lime.
Unfired clay materials also have relatively low embodied energy and carbon. The brickwork in the test house had embodied energy of 146 kwh/tonne and embodied carbon of 44.6 kgCO2/tonne. This is about 14% of comparable fired brickwork and 24% compared to light-weight blockwork. While the bricks were removed from production before kiln firing, they still required two days of artificial air drying.
The estimated saving in this building is 24.9MWh and 7036kg of CO2 over common bricks, and 14.5MWh and 4104kg CO2 over light-weight concrete blocks.
An ability to regulate moisture is another key quality of unfired clay materials. Their hygroscopic scope to absorb and desorb atmospheric moisture allowed the 15mm clay plaster surface in the house to strongly regulate short-term peaks. In the bathroom, the clay plaster had such a strong ability to absorb peaks of air moisture after showers that it cleared the air without surface condensation. The effect of the extractor fan was of no statistical significance.
The brick core had a longer term moderating effect, peaking at two hours after exposure to moisture, but continuing for over 24 hours.
The ability of a building’s fabric to passively avoid conditions where condensation will occur improves its long-term durability and avoids the need for vapour control membranes, which are prone to defects from poor workmanship.
However, the main advantages in moisture terms are to human health through the regulation of internal air relative humidity (RH).
Used on the inside of a layered construction, the unfired clay bricks made a significant contribution to thermal comfort, with warm surfaces and thermal mass that moderated atmospheric temperature swings for up to a week. Effective U-value (the rate of heat loss) of the walls was 32% better than the design calculation, though the reason for this was unclear. The improvement may relate to optimisation of the density of the cellulose insulation or a better than predicted performance by the earth brick and plaster related to air in the earth pore structure.
Whatever the explanation, the walls of the building performed significantly better than was indicated by the design calculations and exceeded the requirements of the contemporary building regulations.
Down to earth
The future for earth construction in the UK remains uncertain. Unfired clay's fundamental properties as a flexible, healthy, low-energy binder give it great potential in an evolving sustainable construction industry. Earth masonry construction is simple and cheap, and could help establish a basic mass-market for earth materials in the mainstream sector, fostering more exciting research and development into prefabricated composite materials and spray applications.
But the commercial reality is that while some major brick producers are developing unfired products, the kind of investment that is needed for a progressive leap is still some way off.
Arc Architects led this research in association with Dundee University, UK, and Robert Gordon University, UK.
Terça-feira, 10 de Fevereiro de 2009
en San Carlos de Bariloche, Argentina
Grupo de Construccion Natural Bariloche
Arq. Juan Carlos Patrone (FADU-UBA/terrabaires)Arq. Liliana Alvarez (Asociacion Proteger/GEA Argentina)
Arq. Rodolfo Rotondaro (CONICET/terrabaires)
Curso intensivo con clases teóricas y práctica constructiva para el conocimiento de materiales,componentes básicos, y manejo de herramientas y equipos. Debate y discusión con alumnos.
Pobladores y albañiles, autoconstructores,Técnicos y profesionales, Maestros,Líderes comunitarios, Funcionarios ONGs y fundaciones, Instituciones públicas y privadas
Min. 20 - Max. 30 alumnos
Costo de capacitación total: $ 250,-
Ensayo de contracción lineal (caja Alcok).Mezclas. Resistencias. Criterios de selección.
Desde hace más de treinta años las construcciones de tierra son objeto de análisis,promoción, difusión, enseñanza y transferencia en todo el mundo, mediante actividades que van desde el simple mejoramiento de los suelos hasta proyectos y obras complejas.
aprovechando la mano de obra local.
y de cohesión interna.
This long construction, which runs from north to south with two floors above ground and a basement, gently follows the contours of the mountainside.
Reinterpreting traditional local wooden constructions, it is made of stone, wood, rammed earth and glass.
In each room, all facing east or west, rammed earth walls separate the sleeping quarters from the bathroom.
The accessible landscaped roof helps prevent overheating while the large glass windows exploit solar energy, adjustable shutters on the façade control the mount of shade.
Class A architecture, won the WWF’s Golden Panda Award in 2006 and
the Legaambiente/Lombardy Region Award in 2006.
Em 1913, foi construído um dos primeiros teleféricos do mundo para chegar a San Vigilio.
Actualmente o Vigilius Mountain Resort, uma extensão do antigo Vigiljoch Hotel, pode apenas ser alcançado por teleférico ou a pé, apenas uma característica especial da forma como ele interage com a natureza circundante. Esta longa construção, que segue de norte a sul com dois pisos acima do solo e uma cave, segue suavemente os contornos da encosta. Em torno uma rede de percursos reforça a ligação entre o edifício e a topografia da envolvente. Reinterpretando as tradicionais construções locais em madeira, o edifício é construído em pedra, madeira, terra e vidro. Apenas as áreas em cave são feitas em betão armado reforçado.
No extremo sul do empreendimento encontra-se um SPA ao longo de três níveis e uma piscina, passando por um jardim interior plantado com árvores lariços que formam um autêntico fragmento da região florestal integrada no Arquitectura.
O desenho do telhado acessível ajuda a evitar o sobreaquecimento, enquanto as grandes janelas de vidro exploram da melhor forma a energia solar e as persianas ajustáveis sobre a fachada controlam o emsombramento. Tudo é devidamente detalhado, o controlo da ventilação com recolha de calor e a utilização de painéis radiantes nos interiores, bem como o aquecimento por biomassa que permite para ajudar os agricultores locais e salvaguardar as florestas envolventes, com a utilização de madeira de baixa qualidade como fonte de energia na forma de pellets.
Vigilius Mountain Resort é assim uma suave e elegante estância turística abrangendo um total de 1400 metros quadrados, um luxuoso edifício em harmonia com a paisagem, que propícia uma mistura de bem-estar e sofisticação para os utilizadores, e uma proposta sustentável para o ambiente.
Sexta-feira, 6 de Fevereiro de 2009
David is the principal of his own architectural firm and its companion consultancy which is the vehicle for his pioneering technical work in rammed earth construction. He believes rammed earth will become ever more widely accepted and used over the next decade as more people become aware of it, and as the relative cost of other building materials increases - something he believes is inevitable.
Rammed earth was relatively labour intensive - about 60 percent of the cost of rammed earth construction is labour, David said. A wall can be constructed at about the rate a tradesperson could lay a brick wall.
David attributes his initial interest in earth construction techniques to 'romanticism'. "I was of the 60's generation, which was strong on idealism, and as an architect imbued with a good measure of idealism, earth construction appealed.
When he started investigating the potential of earth construction, it soon became apparent that, largely because of the labour requirement of many forms of earth construction, rammed earth was the only commercial option in the Australian context, and since the 1980s, David and his associates have concentrated on rammed earth techniques.
In 1985, David travelled through the western provinces of China to learn more about the traditional earth construction methods used there and the following year he gained a Churchill Fellowship which enabled him to visit France, Germany, Britain and south-west USA to learn first-hand about the earth building techniques used in those countries.
David's focus on rammed earth led eventually to technical definitions of the 'mix' of ingredients necessary for reliable construction; a development which he sees as the key to the potential of rammed earth as a modern construction material. "We set out to work out why some mixes worked and others didn't, and the end result is a physical and chemical definition of the necessary mix characteristics based on standard engineering analyses".
He is also involved in the final stages of trialling additives which will stabilise clays -an essential ingredient of the rammed earth 'mix' - and so prevent degradation of rammed earth construction by water. "Too much water can, in some instances, destabilise the clay particles and break down the mechanical bond formed between the particles. We have identified and patented additives which prevent that."
David believes identification of the additives, and definition of the physical and chemical characteristics of the construction mix, are the two biggest steps forward in the technical development of modern rammed earth construction: "We have taken the guess work out of the process. We are still using the traditional methods - compacting earthen material between forms which determine the shape of the construction - but in the past, determining the material to be used was a matter of trial and error or traditional experience. We realised very early on that to work in the modern context, with formal engineering and structural specifications to meet, we needed to be absolutely certain that we could produce consistent, high-quality results every time, building after building, no matter where they were located.
"If rammed earth was to be accepted as a modern building technology, it needed to be applicable to all areas and had to be able to be analysed and understood so engineering tests could be undertaken. At the same time, we wanted to use local material. Knowledge of the essential physical and chemical characteristics of successful rammed earth mixes enables us to develop a technical description of the ideal mix, and we are able to blend local materials to produce mixes with those characteristics."
"Using our knowledge of the characteristics required, we are able to combine local materials, usually from several quarries, to achieve a mix with the necessary physical and chemical properties.
The materials included in a mix, and the proportions to be used, were determined on the basis of standard engineering tests of physical and chemical characteristics, said David. "Once we have worked out the mix, construction is a simple matter of dampening and compaction, as has been done for centuries, although we use modern technology for the compaction and do use one or two additives. We add a very small proportion of cement - about five percent by weight - to maximise erosion resistance, and the new additive to prevent bio-degradation as a result of excess moisture will become a standard part of the mix."
With the technical side under control, David and his associates set out to promote awareness and appreciation of rammed earth construction through its use in prestige buildings. "We formed a construction company specialising in rammed earth techniques and set about winning a major project to boost its profile. We needed to show that rammed earth was good structurally and, from a design perspective, complied with current design and technical requirements, and was cost effective. We reasoned that a major project would increase public awareness of rammed earth and we would see a 'trickle-down' effect, which has happened.
"We needed to convince people we could build practical, commercial structures."
David Oliver is head of Greenway Architects and CEAC building consultancy. For contact details, see the Alternative Directory under Architects or Earth Builders or Ethical Building/Design Advisory Groups.