Compressed earth block technology, which is anchored in an initial concern to provide a new, economically and socially relevant response to housing production for the very poor, has continued to focus on this concern as its area of application has developed. Tens of thousands of family or communal homes and educational and health facilities have indeed been built since the early 1950s, when this building material emerged in its present form, at the CINVA Centre in Bogota, Colombia. These buildings have gradually confirmed the appropriation of this building technology. This simple building material, directly descended from the most ancient building traditions of the unbaked earth brick and from the fired brick, is capable of the same building and architectural subtlety and the same capacity for adaptation to the broad spectrum of factors – physical, ecological, social, economic and technical -which dictate the production of the built environment.

As a building material, it has come to the fore by demonstrating its usefulness, which can be measured in technical and economic, but also in human terms. From a technical point of view, compressed earth block technology is firmly propped up by a scientific body of knowledge which is the equal of knowledge developed for other kindred building materials used in masonry. From an economic point of view, the compressed earth block, which has the advantage of being able to be locally produced and directly used, is today comparable and sometimes more competitive, depending on the context in which it is applied. As far as production and construction distribution chains are concerned, the technology generates employment across a wide range of jobs, from quarrying to brick-manufacturing, from builder to entrepreneur. In architectural terms, the compressed earth block ensures high quality results and at the same time, given optimum conditions of use, enables the foreign currency and energy savings which are essential to its relevance from a development point of view. At a human level, this technology provides concrete responses to the basic issue of improving the built environment and therefore the well-being of societies. Better quality construction and architecture, accessibility and replicability are the main criteria for evaluating this relevance from a human and economic view-point. This relevance is possible only if the scientific and technical body of knowledge has been mastered, as well as the practical skills. Today, we are talking about a technology which has not only achieved a level of
industrial potential with production methods suited to the formal production sector, but also been able to remain on the scale of craft production and safeguard a degree of usefulness which is relevant to informal sector applications. This dual advantage can serve a wide range of architectural applications in the field of both housing and public facilities. The success of contemporary cases, notably the example of applications on the island of Mayotte (Comoro), confirms this dual advantage placed at the service of development ensuring economic and social spin-offs for the local population. This ratification needed to be confirmed by building up a body of knowledge and skill capable of being transmitted and appropriated, starting from high quality architectural examples. This is in fact what has in many instances occurred, as is shown in the monographs which are discussed later and intended as much for land-use decision-makers as for architects, engineers or entrepreneurs; a book designed to boost confidence and supply the practical tools which seem to us, at the term of our research and field experience, indispensable; a manual designed to disseminate this knowledge and skill towards a wider area of application, but most particularly towards housing and public facilities for local communities who have no choice but to use earth as a basic building material and who have a legitimate desire to benefit from modern technology. Such is compressed earth block technology, at the crossroads between traditional earth building customs and modern masonry building practices, a technology which offers an alternative whilst remaining within a range of high quality architectural applications.

Advantages of Using Compressed Earth Blocks

Advantages of CEB include:

Uniformity – Use of local materials – No transportation costs – Faster construction time – Less waste – No pollution

The soil used to make the bricks is sub-soil, which leaves the top soil for agriculture. A good brick making soil can usually be found at the construction site or within a short distance.

History
Brick walls have been in use for several thousands of years; India and other near eastern countries first started building brick walls about 5000 years ago. The ideas behind the way brick walls and bricks are made have changed little over the years. Even the size of bricks has stayed relatively unchanged. Bricks designed for the construction of brick walls can also be referred to as compressed earth blocks, or CEBs. As the name implies, bricks are made by compressing a type of earth such as shale or clay. The actual shape of the brick can be produced in two different ways: the soft method and the stiff mud process. The soft method is when the clay is compressed into a form. The other way of shaping brick is the stiff mud process, where the earth is pushed through the form and then cut to the desired size. Either way, the brick needs to be powerfully compressed. The more a brick is compressed, the more it adds to the durability of the final brick wall. A brick that has been highly compressed will absorb less water and can be used in outdoor applications where the brick wall is exposed to rain and other weather conditions.

The compressed earth block is the modern descendent of the molded earth block, more commonly known as the adobe block. The idea of compacting earth to improve the quality and performance of molded earth blocks is, however, far from new, and it was with wooden tamps that the first compressed earth blocks were produced. This process is still used in some parts of the world. The first machines for compressing earth probably date from the 1 8th century. In France, Francois Cointeraux, inventor and fervent advocate of “new pise” (rammed earth) designed the “crecise”, a device derived from a wine-press. But it was not until the beginning of the 20th century that the first mechanical presses, using heavy lids forced down into moulds, were designed. Some examples of this kind of press were even motor-driven. The fired brick industry went on to use static compression presses in which the earth is compressed between two converging plates. But the turning point in the use of presses and in the way in which compressed earth blocks were used for building and architectural purposes came only with effect from 1952, following the invention of the famous little CINVA-RAM press, designed by engineer Raul Ramirez at the ClNVA centre in Bogota, Columbia. This was to be used throughout the world. With the ’70s and’80s there appeared a new generation of manual, mechanical and motor-driven presses, leading to the emergence today of a genuine market for the production and application of the compressed earth block.

Since its emergence in the ’50s, compressed earth block (CEB) production technology and its application in building has continued to progress and to prove its scientific as well as its technical worth. Research centers, industrialists, entrepreneurs and builders have developed a very sophisticated body of knowledge, making this technology the equal today of competing construction technologies. CEB production meets scientific requirements for product quality control, from identification, selection and extraction of the earth used, to quality assessment of the finished block, thanks to procedures and tests on the materials which are now standardized. This scientific body of knowledge ensures the quality of the material. Simultaneously, the accumulated experience of builders working on a very large number of sites has also enabled architectural design principles and working practices to emerge and today these form practical points of reference for architects and entrepreneurs, as well as for contractors.

The setting up of compressed earth block production units, whether on a small-scale or at industrial level, in rural or urban contexts, is linked to the creation of employment generating activities at each production stage, from earth extraction in quarries to building work itself. The use of the material for social housing programs, for educational, cultural or medical facilities, and for administrative buildings, helps to develop societies’ economies and well-being. CEB production forms part of development strategies for the public and the private sector which underline the need for training and new enterprise and thus contributes to economic and social development. This was the case in the context of a program on the island of Mayotte, in the Comoro islands, for the construction of housing and public buildings, a program today regarded as an international reference. The use of CEBs which followed the setting up of an island production industry proved to be pivotal in Mayotte’s development, founded on a building economy generating employment and local added value in monetary, economic and social terms.

CEB represents a considerable improvement over traditional earth building techniques. When guaranteed by quality control, CEB products can very easily bear comparison with other materials such as the sand-cement block or the fired brick. Hence the allegiance it inspires amongst decision-makers, builders and end-users alike.
CEB technology has made great progress thanks to scientific research, to experimentation, and to architectural achievements which form the basis of a wide range of technical documents and academic and professional courses. A major effort is now being devoted to the question of norms and this should help to confer ultimate legitimacy upon the technique in the coming years.