Seismic resistance of earth construction in Portugal

This paper presents an assessment of the potential seismic performance of new earth construction in Portugal. Results of a parametric study on a properly designed rammed earth construction, considering several strengthening solutions, are presented and discussed. It is concluded that single storey houses can have acceptable seismic performance even in high seismicity areas, provided that the structure is adequately strengthened by reinforced concrete columns and beams. Improvement of the characteristics of the structural material (earth) may be necessary to reduce damage.

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

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, it shows that it is essential to adjust the requirements to the specificities of local materials.

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

International Journal of Architectural Heritage, 8: 185–212, 2014

Provide instructions and resources for assessment and training in earth building: the Pirate project

This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.

Approximation to earth material from international normative

For centuries, earth has been used as a construction material. Nevertheless, the normative in this matter is very scattered, and the most developed countries, to carry out a construction with this material implies a variety of technical and legal problems. In this paper we review, in an international level, the normative panorama about earth constructions. It analyzes ninety one standards and regulations of countries all around the five continents. These standards represent the state of art that normalizes the earth as a construction material. In this research we analyze the international standards to earth construction, focusing on durability test (spray and drip erosion tests). It analyzes the differences between methods of test. Also we show all results about these tests in two types of compressed earth block.

Hydric behavior of earth materials and the effects of their stabilization with cement or lime: study on repair mortars for historical rammed earth structures

Earthen building materials bear interesting environmental advantages and are the most appropriate to conserve historical earth constructions. To improve mechanical properties, these materials are often stabilized with cement or lime, but the impact of the stabilizers on the water transport properties, which are also critical, has been very rarely evaluated. We have tested four earth-based repair mortars applied on three distinct and representative rammed earth surfaces. Three mortars are based on earth collected from rammed earth buildings in south of Portugal and the fourth mortar is based on a commercial clayish earth. The main objective of the work was over the commercial earth mortar, applied stabilized and not stabilized on the three rammed earth surfaces to repair, to assess the influence of the stabilizers. The other three earth mortars (not stabilized) were applied on each type of rammed earth, representing the repair only made with local materials. The four unstabilized earth materials depicted nonlinear dependence on t1/2 during capillary suction. This behaviour was probably due to clay swelling. Stabilization with any of the four tested binders enabled the linear dependence of t1/2 expected from Washburn's equation, probably because the swelling did not take place in this case. However, the stabilizers also increased significantly the capillary suction and the capillary porosity of the materials. This means that, in addition to increasing the carbon footprint, stabilizers like cement and lime have functional disadvantages that discourage its use in repair mortars for raw earth construction.

Mechanical properties of adobe blocks used in building construction in Huambo Province - Angola

Despite significant advances in building technologies with the use of conventional construction materials (as concrete and steel), which significantly have driven the construction industry, earth construction have demonstrated its importance and relevance, as well as it has matched in an efficient and eco-friendly manner the social housing concerns. The diversity of earth construction techniques allowed this material to adapt to different climatic, cultural and social contexts until the present time. However, in Angola, the construction with earth is still associated with population fringes of weak economic resources, for which, given the impossibility of being able to acquire modern construction materials (steel, cement, brick, among others), they resort to the use of available natural materials. Furthermore, the lack of scientific and technical knowledge justifies the negative appreciation of traditional building techniques, and the derogatory way how are considered the earth constructions in Angolan territory. Given the country's current development status, and taking into account the environmental requirements and the real socio-economic sustainability of Angola, it is considered that one of the viable and adequate options, could be the recovering and upgrading of the ancestral techniques of earth construction. The purpose of this research is to develop the technical and scientific knowledge in order to improve and optimize these construction solutions, responding to the real problems of housing quality as well as to the current social, economic and environmental sustainability requirements. In this paper, a description of the physical and mechanical characteristics of the adobes typically used in the construction of traditional houses in some localities of Huambo, province in Angola, is carried out. The methodology was based on mechanical in-situ testing in adobe blocks manufactured with traditional procedures: i) tensile strength evaluated with the bending test and compressive strength test on earth blocks specimens; and, ii) durability and erodibility test by Geelong method adopting the New Zealand standard (NZS) procedures (4297: 1998; 4297: 1998 and 4297: 1999). The results allow the characterization of the materials used in the construction of raw earth in the Huambo region, contributing to the development of knowledge of these sustainable and traditional housing constructive solutions with a strong presence in Angola [1, 2]. This study is part of a larger project in the area of Earth Construction [3], which aims to produce knowledge which can stimulate the use of environmental friendly construction materials and contribute to develop constructive solutions with improved performance, durability, comfort, safety and sustainability.

Improving building technologies with a sustainable strategy

In recent years it has been noticed the progressive disappearance of vernacular sustainable building technologies all over the world mainly due to a strong urban rehabilitation process with modern technologies not compatible with ancient knowledge. Simultaneously new dwellings are needed all over the world and in this sense it was decided to study an ecological and cost-controlled building technology of monolithic walls that can combine the use of low carbon footprint materials, such as earth, fibres and lime using an invasive species: giant reed cane (Arundo Donax). This paper explains the development of this building technology through testing diverse prototypes.

HLT Hilotec: self-building manual for sustainable housing

The future of the construction industry will require changes at many levels. One is the ability of companies to adapt to new challenges, converting needs to opportunities and simultaneously contributing to the solving of social and environmental problems. In the coming decades we will see a change in attitude in the industry, with a strong tendency to adopt natural and recycled materials, as well as bet on green technology and social innovation oriented to emerging countries. On the other hand, emerging countries have a high demand for housing construction on a large scale, but the current techniques in the developed countries for building requires a large amount of natural resources and skilled labor. This contextualization brings sustainability problems for the construction sector in emerging countries, often with scarce natural resources and with the construction sector underdeveloped. Through a cooperative action between the construction company Mota-Engil Engineering and the University of Minho in Portugal, a construction technology was developed based on the use of Compressed Earth Blocks as part of a social concept for innovative small houses, favoring the adoption of local and natural materials and with the main premise of being dedicated to self-construction. The HiLoTec project - Development of a Sustainable Self-Construction System for Developing Countries was based on this idea. One of the several results of this project is this construction manual. To Mota-Engil the project was a platform for incubation of knowledge about earth construction and to obtain a constructive solution validated technically and scientifically, suitable to be implemented in the markets where it operates. For the University of Minho the project was an opportunity to strengthen skills in research, laboratory and scientific development, through the development of engineering studies, architecture and sustainability, as well as supporting the doctoral scholarships and dissemination of scientific publications. May the knowledge of this project be of benefit, in the future, for the welfare of those who build a HiLoTec house.

Desenvolvimento e validação de uma solução construtiva em BTC

Dissertação de mestrado integrado em Engenharia Civil

Análise experimental do comportamento ao corte de paredes reforçadas em alvenaria de BTC

Dissertação de mestrado integrado em Engenharia Civil

Comportamento térmico de blocos de terra comprimida ativados alcalinamente

Dissertação de mestrado integrado em Engenharia Civil

Comportamento acústico de blocos de terra compactada ativados alcalinamente

Dissertação de mestrado integrado em Engenharia Civil

Puun ja turpeen seospolton vaikutus tuhkan hyötykäyttökohteisiin

Työn tavoitteena oli selvittää puun ja turpeen seospolton vaikutukset tuhkien hyötykäyttökohteiden valintaan laitoksella tehtävien koeajojen ja kustannus- sekä SWOT-analyysien avulla. Lisäksi tavoitteena oli selvittää lainsäädännön vaikutukset tuhkien hyötykäyttöön. Kustannusanalyysissä tarkasteltiin tuhkien hyödyntämisen nykytilan lisäksi rakeistuslaitosinvestointia ja selvitettiin eri hyötykäyttövaihtoehtojen etuja ja haittoja. Lainsäädäntö vaikuttaa oleellisesti tuhkien hyötykäyttöön. Hyötykäyttöä säädellään sekä kansallisella että EU-tasolta tulevalla lainsäädännöllä. Ympäristölainsäädännön ja etenkin jätelainsäädännön kokonaisuudistuksen myötä myös hyötykäyttöä koskevat lainsäädäntö uudistui. Energiantuotannon tuhkat tulivat jäteverolain piiriin ja lannoiteasetuksenuudistuksella pyrittiin helpottamaan tuhkien lannoitekäyttöä. Myös jäteluokittelu ja sen päättyminen tuhkien osalta vaikuttaa olennaisesti tuhkien käsittelymenetelmien ja hyödyntämisen kannattavuuteen. Jäteluokituksen päättyminen voi viedä tuhkat kemikaalilainsäädännön piiriin. Kustannus- ja SWOT-analyysissä selvitettiin tuhkien hyödyntämisen kannalta keskeiset kustannustekijät. Rakeistuslaitosinvestoinnissa huomioitiin erilaiset tuhkien käsittelymäärät ja niiden vaikutukset kustannuksiin ja investoinnin kannattavuuteen. SWOT-analyysin avulla selvitettiin hyödyntämisen vahvuudet, heikkoudet, mahdollisuudet ja uhkatekijät. Polttoainesuhteella ei ollut poissulkevaa vaikutusta tuhkien hyötykäyttövalintaan. Lentotuhkat soveltuivat parhaiten lannoitehyötykäyttöön ja pohjatuhkat maarakennushyötykäyttöön. Rakeistuslaitosinvestointi olisi kannattava etenkin suuremmilla tuhkamäärillä.