Linking rheological and geotechnical properties of kaolinite materials for earthen construction

Abstract

Due to its low environmental impact, earth construction has received much consideration in recent years. However, its development is limited by construction time as the strength of the material results from a slow drying stage and not by chemical setting. This means that using conventional rammed earth construction, it is not possible to strike the formwork the day after casting. In order to find another construction technique, many researchers have studied the behaviour of freshly made earth material using different types of admixtures that change the material’s rheology. Conventional dispersants used in the ceramic industry (such as sodium hexametaphosphate) or superplasticizers used in concrete are used to modify the fresh raw earth material. Moreover, earth materials are often described using empirical geotechnical parameters such as Proctor water content or plasticity index that are not directly linked to the material intrinsic behaviour. This paper has two simultaneous goals: the first one is to describe the rheology of kaolinite paste with and without dispersants and the second one is to link the “engineering” geotechnical parameters to the material’s rheology.