Shad Hoover, Whitney Greenawalt and Brian Tittmann (all of CMT Laboratories Inc, State College, PA, USA) have published a paper on the measurement of pyritic shale expansion due to the oxidation of pyrite. The authors use laboratory oxidation experiments and theoretical geochemical models to estimate expansion rates and magnitudes.
The paper is titled “Experimental and Theoretical Modeling of Expansion in Pyritic Shale”.
“Expansive pyritic shales are found in black carbonaceous shales throughout the United States as well as in other countries, including Ireland, England, Norway, Canada, and Sweden. Expansion occurs when the pyrite, which occurs either as finely disseminated syngenetic framboids, macroscopic crystals, or diagenetic replacement fossils, oxidizes to form sulfuric acid.
Andreia Rodrigues and others at the Centre de Recherche sur les Infrastructures en Beton (Universite Laval) in Quebec, Canada have published a paper on the development of a laboratory test that attempts to reproduce the deterioration of mortar due to the oxidation of sulfide minerals in sulfide-bearing aggregate.
The paper, titled “A new accelerated mortar bar test to assess the potential deleterious effect of sulfide-bearing aggregate in concrete” adds to previous research by the authors on problems related to iron sulfides in concrete in Canada. The full abstract from Cement and Concrete Research is shown below.… Read the rest