Eco-efficient earth plasters: effect of cow dung and air lime on a kaolinitic clayish earth

Earth mortars are eco-efficiently used as plasters, but not all raw earth have a composition and
behavior to meet the plasters nowadays requirements. Since long time ago, some stabilizing
materials are often added to improve some characteristic of the earth mortars. Thus, to compare
the performance of an industrial stabilizer recognized by the literature with a natural stabilizer
already established by the Brazilian vernacular construction tradition, this research compared the
effects caused by the addition of hydrated air lime and cow dung on the physical and mechanical
properties of an earth mortar produced with a Kaolinitic Clay Earth (KCE). For this purpose,
laboratory tests were carried out, following the guidelines of the German standard DIN 18947 for
the analysis of earth plastering mortars. The results show that the earth mortars stabilized with
cow dung presents superior results in all tests performed. Therefore, this is a material with great
potential to be investigated as a stabilizer in earth plastering mortars.