The quality of the concrete facings results from the implementation of release agents and the casing surface quality. It is interesting to characterize the behaviour of release agents over the lifetime of the formwork. This study is based on the many ones test physicochemical and esthetics realized on two types of surface of formwork like on three types of applications. In complement, the ageing of the casing formwork was characterized by electrochemical spectroscopy of impedance and thanks to the correlation with the aesthetic tests will allow to find from new mechanisms to the interfaces related to the studied oil's formulations. (C) 2014 Elsevier Ltd. All rights reserved.