Earthen buildings form one of the largest building stocks worldwide. This is true for more humble buildings, whilst of the 563 cultural sites that were inscribed on the World Heritage list, 17% are fully or partially built with earth (UNESCO). Conservation and sustainable development are two disciplines that seem to be uncomfortably far from one another. However, there are several advantages in conserving earthen buildings: reduction of carbon footprint, improvement of occupant health due to building quality, and keeping with cultural continuity. The environmental credential of earth as building materials relates to the fact that manufacturing and conservation does not deplete significantly finite natural resources, but also that handmade, air-dried materials have the lowest embodied energy and recycling or disposal does not require high levels of energy. Earth materials create low levels of waste and generally cause no direct environment pollution during the whole life cycle. However, if not properly protected, earthen materials can be vulnerable to decay and damage. In fact, earthen buildings present a very low tensile strength, a low compressive strength and a fragile behaviour, and are generally speaking vulnerable to earthquakes. These considerations, and the present lack of guidelines for the conservation of earthen buildings, point to the necessity of studying proper diagnosis techniques with the objective of being the basis for adequate intervention methods. The aim of this paper is to provide an overview of available tests both for earth material characterization (chemical, physical and mechanical) in the laboratory, and in situ estimation of its morphology and its mechanical behavior.
One-fifth of Australia’s greenhouse gas emissions come from households. There are 7 million households in Australia and each is producing about 15 tonnes of greenhouse gas every year. Energy use, car use and waste are the largest sources of household emissions. Improving the energy efficiency of homes is one of the most effective ways of reducing greenhouse gas emissions and has been the main focus of the government’s energy policy. In addition to the introduction of BASIX as mandatory to all new homes in NSW in 2004, the federal and state governments have introduced incentive schemes to subsidize Australian homes to install solar panels and other renewable energy technologies as a way to improve energy performance of existing homes since 2006. This paper examines the opportunities and challenges of renewable energy in improving energy efficiency of existing dwellings. The paper also presents the results of an economic analysis of renewable energy source in a dwelling in NSW. Finally a strategic direction of providing affordable and environmentally sustainable practices in upgrading existing homes to improve energy efficiency is also developed and discussed.
Due to the awareness of the exhaustion of energy resources, some studies on construction techniques, linked to local traditions, to readily available materials, to low load energy and to self-building are been carried out. The high recyclability of natural materials that can be used in low-cost buildings (such as clay, straw, bamboo, wood) associated with construction techniques capable of exploiting the principles of bioclimatic architecture for energy needs, allow us to create building environmentally conscious and responsible. This study was developed according to the following steps: at first, we proceeded to collect information on the state of art. In particular, we analyzed different types of construction based on clay solutions (rammed earth – pisè, hand-formed bricks – adobe, lightened earth, weight-reduced blocks-massoni, cob, extruded blocks, compressed blocks) and different types of materials and/or compositions of clay/sand/straw mixture (clay and straw, clay and wood, clay and minerals aggregates). A series of earthen construction projects has been investigated, in order to identify their technology choices and design, in relation to operational, manufacturing, and constructive aspects. These data were then compared in terms of energy performance, maintainability, flexibility, comfort. The next step involved the design of a habitation module of transitory residencies with wooden framework and outside walls in lighter earth hand-formed blocks. At the same time the project of a special block (made of clay and fibers derived from foliage of common reed – Arundo Donax) was developed, to meet the needs of sustainability and ease of construction. An experimental test on this block was carried out, aimed at the identification of mechanical performance in relation to the different compositions of the mixtures.
At the end of the 19th and at the beginning of the 20th centuries Budapest the capital of the Hungarian kingdom underwent a significant development. During this period the number of inhabitants of the city multiplied, as a consequence several new city districts were constructed. The functional and structural arrangement of these new residential buildings was very similar in respect of the materials used and the technologies applied. A considerable part of these buildings still constitutes the determining element of the townscape. It is one of the most burning issues of the present day Budapest that a part of these buildings are in very bad condition. Due to the limited financial resources it is an essential task to set up priority ranking of the renovation, upgrading and renewal of buildings with similar arrangement. In our case the traditional (two-valued) logic is unsuitable for modelling or handling the given phenomenon. When describing the status of a load-bearing building structure the terminology of ‘appropriate condition’ cannot be handled by Boolean logic, since it cannot be strictly determined where the borderline is between appropriate or inappropriate condition. In the case of the majority of the linguistic characteristics of this type there is a well noticeable joint element, which expresses a kind of inaccuracy or uncertainty. For such tasks the application of fuzzy signatures is considered to be one of the possible solutions. The fuzzy type inaccuracy somehow links with human thinking. Fuzzy logic is an extension of the two-valued logic, which makes it possible to define transitions, too. By applying the fuzzy singleton signatures a status-determining and ranking model was created, which is suitable for the qualification and ranking of buildings of similar age and structural arrangement. This model was used for the first time on a database, which is based on expert opinions, relating to a given stock of residential building. The modelling of the load-bearing structural condition of the residential buildings is a complicated task, the components where of are well-structured and a hierarchical structure can be built therefrom. Based on the foregoing a tree-structure, necessary for the examination of the load-bearing structures of buildings, has been proposed. In this framework primary and secondary structures were distinguished during the examination, which would be linked with qualification values based on their arrangement, materials and conditions (in accordance with fuzzy logic). The significance of the load-bearing structure of various building elements was taken into account by using relevance weights. For the aggregation of the fuzzy singleton signature the Weighted Relevance Aggregation Operation (WRAO) was used. The aggregate status descriptors, characteristic of the status of a building, provided the basis for the ranking of buildings in case of a certain stock of buildings. Discrepancies of the results achieved by method using membership functions of approximate and fine set of values, conclusions were drawn as to when and which method should be used in practise. The results of this study may make it easier to realize rehabilitation ideas of similar residential areas, and also can be efficiently used during utilization and renewal of certain buildings in bad condition.
Nowadays, fire remains a risk with potentially severe consequences for most buildings and structures. In fact, beyond the physical damage to the structure, which may require their subsequent repair or demolition, the fire also implies risks for the safety of occupants. Concrete exposure to high temperatures causes a progressive physical and chemical degradation that changes its microstructure and properties. Experimental studies have already been carried out on different types of concrete, under temperature increase. Lightweight, standard and high strength concrete, reinforced with various types of fibers has already been studied. The various types of concrete have shown significant differences in their behavior. However, the behavior of concrete containing cork was not yet studied. In the present study, cork concrete specimens were subjected to high temperatures (ranging from 90°C to 600°C). The specimens were produced replacing the amount of sand from a reference composition with several percentages (20, 25, 30 and 40%) of a mixture of granulated cork expanded. The results were analyzed and compared with those obtained for identical concrete samples that were not subjected to heating. The results revealed that the presence of cork has a beneficial effect on the residual strength of concrete subjected to high temperatures. Despite the reduction of concrete strength with increasing temperature, concrete batches with higher cork amounts reported lower percentage strength reduction.
In the immediate aftermath of the earthquake in L’Aquila in April 2009, various new regulations and operational methods were defined to enable reconstruction to begin as quickly as possible. This brought opposing dynamics to bear on the urban and territorial system of L’Aquila and the numerous surrounding small settlements that historically played a part in its original foundation. Currently the most important issue is to rebuild the city and its system of outlying villages, at the same time seeking to identify new functional models and models of habitation. With this in mind the reconstruction plans aim for seismic improvement and improved living conditions by making organic interventions that ensure the overall consolidation, safety, habitability and functionality of these built systems in their entirety, in full respect of their existing historic and contextual values. As part of this integrated approach and in consideration of the complex issues involved, this paper presents the first outcomes of the activities of support provided to the municipality of Sant’Eusanio Forconese to assist in preparing the reconstruction plan for this ancient village, which in terms of its morphology, its building types, and its construction methods is an excellent exemplar for all the settlements that lie within the earthquake crater.
