Specific surface area and saltweathering of limestones : a laboratory study

Abstract

Specific surface areas (SSA) results are used to discuss results of salt weathering tests of two grainstones and a travertine. SSA was found to be especially useful in the understanding of the travertine heterogeneous behaviour (with higher SSA in the clay-richer zones) and the conclusions can be considered transferable to travertines in general. The transferability of conclusions applies insofar as in these continental limestones the terrigenous clay-rich zones, whose composition was verified by the infrared spectra, would promote mesoporous portions that favour the migration of solutions and that are, hence, more susceptible to salt weathering. SSA did not distinguish the grainstones types (Semi-rijo and Moca Creme), which present different weight loss in the salt weathering tests (higher in Moca Creme), a result explained by the predominant macroporous (IUPAC sense) character of these rocks. These results suggest that petrographic studies can be employed in the definition of groups of rocks for which SSA could be used as estimator of mass loss under salt weathering conditions . Other perspectives of the stone cycle are also referred for the travertine considering the presence of a certain amount of pores with nanometric size in this rock and the possible higher specific values of presumably clay-richer residues from its cutting.