Colorimetry of Clays as a Tool to Identify Soil Materials for Earthen Buildings Restoration

Abstract

In the restoration field and the cultural heritage, the treatment of colour is very important, being an important factor for the decisions and interventions in historic buildings. However, some of these have not the same recognition and protection by authorities, being really vulnerable, especially against natural phenomena like the earthquakes. After the 2017 Puebla Earthquake, the remainders of the earthen architecture of Jojutla de Juarez were collected to be analysed. Natural clays of the quarries near the town were compared by colorimetry tests with the traditional adobe samples which were collected in the locality. There also were conducted particle size analysis and the Unified Soil Classification System, USCS, to obtain the composition and properties of the soils and the adobe bricks, as well as the additives used, mainly straw as fibre reinforcements of the adobe masonry. One of the factors observed which contributed to change the colorimetric values of the clays was the use of stabilizers like lime, on the other hand, these stabilizers also helped to change the USCS classification of the soils and their cohesive properties.