Lime treatment is a well-known earthwork technique, for soil improvement and stabilization. Its applications are mainly in road, railway, airport and platform construction. In addition, some positive experiences of lime treatment are related to solve erosion problems of dispersive and non-cohesive soil in hydraulic structures. Lhoist Group, a lime producer, recently launched a series of experimental programs to show the relevance of lime treated soils for earthen hydraulic structure construction or renovation. The paper focuses on the resistance of lime-treated soils vs internal erosion. For this purpose, Hole Erosion Test (HET) can be considered an efficient tool to assess piping flow erosion initiation and development parameters of a material, which are critical stress and erosion coefficient. The evolution of those parameters is followed with ageing time of several lime-treated materials, in parallel with mechanical properties and cohesion that develop thanks to mid to long-term actions of lime, so-called pozzolanic reactions