Physico-chemical characterization of building material in historical rammed earth houses

Abstract

Earthen architecture buildings and the traditional techniques of rammed earth, wattle-and-daub and adobe are an exceptional ensemble of cultural heritage in Brazil, and in particular in the state of São Paulo. This heritage is in danger of disappearing and needs to be protected by adequate preservation policies. These, in turn, require several research actions ranging from the identification and mapping of historical houses built with these techniques between the XVIII and XIX centuries (not always cataloged or protected by patrimonial institutions), to a deep characterization of the materials and existing or potential mechanisms of physical, chemical and biological deterioration. It should be noted that the permanence of the buildings on land is fundamental to guarantee the maintenance of concrete physical testimonies of the models of civil construction in the different moments of our history. The present proposal will address the physico-chemical composition of historic buildings built using the rammed earth technique and its objective will be to deepen knowledge on the different solutions adopted for its manufacture in the State of São Paulo based on a detailed study in a significant set of historical buildings located in the municipalities of Sorocaba, Itu and Porto Feliz, a territory with a great wealth of historical heritage built with earth and that exhibits a trajectory of colonization particularly old. To this purpose, the research will involve: the complementation of a bank of rammed earth samples in constructions of these municipalities of different historical periods and soil samples representative of the different features present in the studied territory, the analysis of the physical and chemical characteristics of the samples and the use of such information for the enlightening of the selection criteria and the degrees and the forms of manipulation of the soils for the manufacture of the rammed earth structures.