Weathering rates of marble in laboratory and outdoor conditions
- Univ of Louisville, KY (United States)
- Metro Services Lab., Louisville, KY (United States)
In the modern urban atmosphere SO{sub 2} and NO{sub 2} attack calcite (CaCO{sub 3}) in marble exposed at rain-sheltered surfaces creating largely gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) crusts that eventually exfoliate. In combination with CO{sub 2} these gases erode the marble at unsheltered surfaces. the authors report the development of mathematical models to predict the rate of growth of crust and the rate of surface recession. To determine the rate of growth of crust the kinetic rate constant, diffusion rate, and the order of reaction were determined by the application of the shrinking-core model applied to data generated in laboratory experiments. Based on these parameters /and average ambient levels of 10 parts per billion (ppb) SO{sub 2} and 25 ppb NO{sub 2} in Louisville, Ky., the rate of crust formation for this metro area was calculated to be 1.8 {micro}m in the first year. However, the rate of recession was modeled from data obtained by exposing marble slabs to rainfalls. A surface recession of 15 {micro}m/yr was calculated. The models predicted well the rate of growth of crust observed at several sites in Louisville and the predicted surface recession compared well with values reported in the literature.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 395119
- Journal Information:
- Journal of Environmental Engineering, Vol. 122, Issue 9; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Weight losses of marble and limestone briquettes exposed to outdoor environment in the eastern United States: Results of exposure 1988--1992
Weight losses of marble and limestone briquettes exposed to outdoor environments in the eastern United States