Rheology of aluminosilicate hydrogels*

Thanks to their environmental acceptability and their adaptability over a wide range of applications, alkali solutions of aluminosilicates are increasingly used in nuclear or building and construction industry. Although such solutions are increasingly used in the industry, there remain outstanding questions regarding the gelation process, that are driven by the composition of the solution, their stabilities and their aging. It is therefore crucial to provide a clear and realistic description of such fluids in order to tune and taylor macroscopic properties.
The aim of this work is to study the linear viscoelasticity properties of the gels throughout a variety of rheological tests, combining with time resolved Small Angle X-ray Scattering (SAXS) from liquid to gelling state. The aluminosilicate gels show a power law behavior that is well described by the Fractional Maxwell Model (FFM). The derived parameters of the FFM are well correlated to the fractal dimension that can be directly extracted from the SAXS measurements. Aging of these gels will also be discussed in relation to the results obtained at mesoscale by SAXS