THE STABILIZATION AND THE THERMAL RESISTANCE OF THE RAMMED EARTH

Reasons for the research
The rammed earth arouses very often, even in the technical field, many questions because it seems to be only part of the building traditions of the desert regions in the world, where the use is possible due to absence of precipitation and the sultry heat. Actually few people know that this technique, very ancient and widely practiced, is also widespread in Europe, and in Italy in particular, when they occur at the same time three different conditions: a social structure of rural type, a clay soil and a very low average level of wealth. The earth, in fact, is a poor material or, better, low tech, i.e. such as to require reduced transformation processes: it is thus evident that its use has spread especially among populations that do not have the resources necessary to use materials economically and technically more efficient. But it would be wrong to consider the rammed earth as a kind of fallback to which recourse: if it is true that it requires constant maintenance and small technical measures to protect it from the action of rainwater, we can also say that, as well as having a discrete mechanical behavior, it is able to actively participate to increase the level of thermal quality – and thus the environmental quality – of buildings. Generally each material is never in itself good or bad: are the choices made during the construction process to be more or less correct according to the requirements and benefits comparison. For this reason, if the requirements are not defined, you cannot perform any classification, neither the rammed earth nor any other product for the building. In order to establish its appropriate use in the current scenario, which sees the market presence of compounds with high mechanical performance, it became immediately clear need to conduct measurements directly on specimens because, given the wide variety of soil types , it is not possible to derive the physical characteristics from the scientific literature. This has rather stimulated the idea of being able to determine experimentally the proportions of the different components, by varying the amount of clay and straw present in the specimens, transferring the practice of the mix design from the concrete to the soil. […]