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The will of reducing environmental and social impact of building industry has led to a renewed interest in earth construction. Most of earth construction literature dealt with rammed earth or adobe techniques, but very little with cob. Yet, cob participates in the diversity of vernacular earth construction processes that value local materials and is an alternative to rammed earth and adobe in specific geographical conditions. Conservation of cob heritage also requires a better knowledge of this vernacular construction process. This bibliographical analysis gathered extensive data on cob process and summarized the different cob process variations, attempting to take into account their diversity. This analysis allowed us to provide novel data on cob process, and more specifically, (1) a clear definition of cob with regard to other earth construction processes, (2) a first summarized description of cob process that clearly distinguished its variations, (3) a list of fibres traditionally employed, (4) values and, if possible, average and standard deviation for fibre length, fibre content, manufacture water content, drying times, lift heights and wall thicknesses, (5) a summary of the strategies to manage shrinkage cracks, (6) a criterion on the quality of implementation and/or earth for cob, based on slenderness ration of lifts and (7) a discussion on the evolution of cob process with regard to societal evolutions. [ABSTRACT FROM AUTHOR]

Earth construction is one of the oldest and most widespread construction system. Around 30% of world population lives in earth buildings. About 50% of population in developing countries, including the majority of rural areas, and at least 20% of urban and marginal urban areas, lives in earth buildings. The main general objectives of this study are the behaviour characterisation of adobe and rammed earth constructions along with the research for the development of retrofitting and seismic performance enhancement solutions, considering the relevant earthen heritage built in Portugal. In fact, until the first half of the last century, earth was commonly adopted as a construction material in Portugal. Adobe was used in almost all types of construction in littoral centre, particularly in Aveiro region. The consolidation of the knowledge on this technique and on the mechanical behaviour of adobe masonry will play a fundamental role on the preservation of the earthen built heritage. In addition, it may contribute to the development of innovative earth construction solutions for new buildings, following current concerns but also respecting structural safety demands, which will allow accommodating the increasing interest on this type of building solutions. The mechanical properties of adobe units and mortars were studied and a series of tests for the characterization of the adobe masonry behaviour were carried out, in the Department of Civil Engineering of the University of Aveiro, namely: (i) bond strength and (ii) joint shear tests. Additionally, a full-scale adobe building model was subjected to monotonic and cyclic horizontal lateral loads until failure. The present paper present the main results and conclusions of the experimental campaign developed. [ABSTRACT FROM AUTHOR]

In the conservation of built heritage, earthen ruins rank as one of, if not the most, intractable of problems to be confronted. Lacking the very architectural devices originally in place to combat and control weathering, earthen ruins face rapid deterioration without constant remedial and preventive conservation. Often it is the enormous mass of many ancient earthen ruins that explain their persistence; however, even these will collapse over time from differential erosion, or eventually stabilize as formless lumps. The impossible demands of simultaneously preserving architectural form and fabric (materiality) challenge the archaeologist and conservation professional who attempt to manage both for temporary and permanent display. [ABSTRACT FROM AUTHOR]

This work estimates the behaviour of mortars based on lime, seeking their application as renders of adobe walls. Mortars with binder:aggregate 1:3 volumetric ratio were prepared as is traditionally used in old buildings in central parts of Portugal. Due to specificity of the support, two clays, natural clay bentonite (5 wt.%) and artificial clay metakaolin (20 wt.%) were used as additives to lime mortar to prepare 3 types of blended mortars, besides the air lime reference mortar. Mortar prisms 4 × 4 × 16 cm were analysed to assess mechanical properties and salt resistance. Moreover, the mortars were placed in three ways on old adobes taken from demolished houses and their behaviour was verified by artificial accelerated ageing test. Lastly, mortars were applied on a wall made from traditional adobes, where panels were monitored and trials with adhesion strength and Karsten tubes have been conducted. The results obtained by comparison of the characteristics from all the experimental procedures reveal that mortar containing air lime and 5 wt.% of bentonite fulfils in the best way the requirements in its use as render of adobe buildings. [ABSTRACT FROM AUTHOR]

The first aim of this paper is to provide an illustration of fabric survey, damage assessment, and structural consolidation of the mud brick structures of Al Ain, an oasis in the United Arab Emirates. The buildings mostly date to the turn of the last century and it was concluded that damage of such vernacular architecture is represented by thermal movement, structural cracks, leaning walls, granular disintegration, erosion and creation of preferential channels, and coving. Furthermore, damage caused by animals and by recent interventions was also surveyed. The second aim of the paper is to illustrate the structural consolidation of mud brick masomy by explaining the work undertaken in the mosque of Al Jahili (1891-1898). This includes eroded wall repair, window filling, repair of cracks with the stitching technique, wall top consolidation, and roof repair. [ABSTRACT FROM AUTHOR]

Adobe construction is considered to be an important feature of the international architectural heritage. To achieve the effective preservation of culturally significant adobe structures, the factors that cause their deterioration should be recorded and understood and the result of potential restoration interventions should be evaluated. This study reviews the pathology of adobe structures and the various restoration methods currently in use. Focus is given on the main agents of adobe deterioration and commonly encountered decay mechanisms. The applicability and efficiency of several repair and strengthening techniques currently used in practice or proposed by academic researchers is critically discussed and the gaps that occur in the field of earthen masonry retrofitting are highlighted. An extensive list of references, which reflects the international knowledge and experience on the topic, is also provided. [ABSTRACT FROM PUBLISHER]