 Summary
More and more, one needs to prove that the materials do not alter the environment in which they are located. For example, it must be guarantied that they release none or little substances (such as metals and organic molecules) when they are brought into contact with water. This phenomenon is commonly called « leaching ». Already published results have established this evidence for the metallic trace-elements in the case of mortar and concrete in contact with potable water. The CRIC-OCCN has been a precursor in this domain and has shown that these traces are very small and in the order of ppb (µg/kg). Considering organic molecules, studies remain rare. Indeed, existing one show that for usual quantities of admixtures, the leaching rate remains lower than the analytical limit of detection which is about 500 µg/l. However, it could be objected sometimes that a leaching rate of 500 µg/l wouldn’t be a sufficient guarantee regarding the limits for other substances in the order of µg/l. This PhD-study, initiated by ATILH is performed at the University of Metz and at the CRIC-OCCN. It must enable to evaluate the thresholds and to understand the mechanisms of leaching of the organic admixtures incorporated in the concrete to improve its workability. |