Stable isotopes of carbon and oxygen for the study of carbonation/decarbonation processes in concretes

Stable isotopes of carbon and oxygen are a potential tool for the study of carbonation and decarbonation processes and for the determination of the lime filler proportion vs secondary carbonates. We describe succintly experiments in controlled conditions relative to carbonation process of cements in humid air, and carbonation/decarbonation in an aggressive CO2 solution. Various phases of the processes can be detected using only variations of the natural abundance of 13C and 18O in the carbonates. CO2 slighlty enriched in 13C by artificial means can be used to detect the transfer of CO2 in concretes in place of 14C- spiked CO2 : measurements of stable isotopes are safe, inexpensive and much faster than for 14C.