Reactivity of secondary phases in weathered limestone using isotopic tracers (D and O).

For a long time, limestone has been massively used in stone building and monuments because of its easy extraction and common presence in the landscape. On ancient monuments, mostly built in urban areas, it is exposed to urban-borne pollutants responsible for specific alteration mechanisms and weathering kinetics. Especially, the dissolution of calcite and the precipitation of new phases will affect the limestone pore network, modify the stones capillary properties, and influence the further alteration.

Nanoscale investigation by TEM and STEM-EELS of the laser induced yellowing.

Nd-YAG QS laser cleaning of soiled stone at 1064 nm can sometimes result in a more yellow appearance compared to other cleaning techniques. Especially in France, this yellowing effect is still considered as a major aesthetic issue by the architects and conservators. One explanation states that the yellowing is linked to the formation of iron-rich nanophase(s) through the laser beam interaction with black crusts that would re-deposit on the cleaned substrate after irradiation.

Water content of limestones submitted to realistic wet deposition: a CIME2 chamber simulation.

An experimental chamber (CIME2) has been specially designed to simulate wet atmospheric deposition on limestones used in Paris cultural heritage. This instrument is a complementary tool to CIME, a previously developed chamber dedicated to the simulation of dry atmospheric deposition on monuments and artifacts. The aim of this paper is to describe CIME2 and characterize the wet deposits produced inside it.