Laboratory experiments were carried out on samples of fresh limestone using an atmospheric corrosion testing apparatus designed for the purpose. The experimental results point out the existence of two different reaction mechanisms developing in the presence of SO2 alone or combined with NO2, respectively. The kinetic expression and a multistep genetic model of the total process of sulfation are proposed. Black crusts from monuments were taken on the same lithoid material and characterized from the textural and compositional point of view. They result from dry deposition of atmospheric suspended matter and sulfation of substratum. The limestone in contact with the crusts is chemically weathered by sulfation and dissolution processes related to acid attack, and physically deteriorated by thermal stresses. Comparison between natural and artificial products of decay points out the greater complexity of natural systems with respect to the laboratory simulation, with direct influences on the characteristics of the deterioration products and the decay of substratum.
Inferences from the study of artificial sulfation and natural products of decay
MORONI, Beatrice;POLI, Giampiero
1999
Abstract
Laboratory experiments were carried out on samples of fresh limestone using an atmospheric corrosion testing apparatus designed for the purpose. The experimental results point out the existence of two different reaction mechanisms developing in the presence of SO2 alone or combined with NO2, respectively. The kinetic expression and a multistep genetic model of the total process of sulfation are proposed. Black crusts from monuments were taken on the same lithoid material and characterized from the textural and compositional point of view. They result from dry deposition of atmospheric suspended matter and sulfation of substratum. The limestone in contact with the crusts is chemically weathered by sulfation and dissolution processes related to acid attack, and physically deteriorated by thermal stresses. Comparison between natural and artificial products of decay points out the greater complexity of natural systems with respect to the laboratory simulation, with direct influences on the characteristics of the deterioration products and the decay of substratum.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
