Multiple Isotopic Studies of Calcium Carbonate Growths in Concrete Structures

Author

Danielle M. Schmitt

Date of Award

6-1999

Degree Name

Master of Science

Department

Geological and Environmental Sciences

Department

Geosciences

First Advisor

Dr. J. Bret Bennington

Second Advisor

Dr. Eliot Atekwana

Third Advisor

Dr. George Guthrie

Fourth Advisor

Dr. Alan Kehew

Access Setting

Masters Thesis-Open Access

Abstract

Secondary minerals, predominantly carbonates, forming under concrete structures have received attention in terms of their possible role in the degradation of their hosts. δ¹³C and δ¹⁸O analyses of several calcium carbonate growths collected from bridges in Michigan and New York were performed. The δ¹³C and δ¹⁸O values clustered around -24.7 ± 1(PDB) and 13.7 ± 1(SMOW) ‰, respectively. A positive δ¹⁸O- δ¹³C correlation suggests kinetically driven precipitation involving atmospheric CO2• ¹⁴C activities determined for select samples support the theory that atmospheric CO₂ is involved in the formation of these deposits. The δ¹⁸O values indicate that the oxygen in the deposits is in part derived from atmospheric CO₂. In addition, select samples were dated using the disequilibrium between ²⁶⁶Ra and ²¹⁰Pb, on the assumption that some amount of ²²⁶R is incorporated and there was no initial ²¹⁰Pb. The ages ranged from the 3.8 to 64 years, not unreasonable based on the actual age of the bridge. If true, this provides a means to date calcite minerals found in concrete structures.

Recommended Citation

Schmitt, Danielle M., "Multiple Isotopic Studies of Calcium Carbonate Growths in Concrete Structures" (1999). Masters Theses. 4788.
https://scholarworks.wmich.edu/masters_theses/4788