Acidic weathering of carbonate building stones: experimental assessment

Abstract

Three types of carbonate rocks, travertine, limestone, and marble have been studied to determine their selected technical parameters (water absorption, resistance to salt crystallization damage) and reaction to experimentally modelled acid rain weathering, imitating the polluted urban atmospheric conditions. The acidic agents present in the natural acid rain precipitation, H 2 SO 4 , HCl, HNO 3 , CH 3 COOH, and the mixture of these acids ("Acid mix"), were tested. The initial stages of acid weathering involve, apart from chemical dissolution, particularly intense physical detachment of rock particles (granular disintegration) significantly contributing to the total mass loss. Travertine was found to be most prone to salt crystallization damage and to acid weathering, and these features should be taken into account especially in external architectural usage of this stone in cold climate conditions and polluted urban atmosphere.