Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
The influence of combustion-derived pollutants on limestone deterioration: 1. The dry deposition of pollutant gases
This study concerns the relative chemical degradation effects of dry deposition of combustion-derived atmospheric pollutants, HCl, SO2 and NO2, on Portland and Monks park limestones, employing laboratory exposure chambers for periods of 30 days. Using presentation rates up to 40x10-10 g cm-2 s-1, the pollutants were assessed individually and in various combinations, along with ozone as oxidant, at 84 % RH with dry or water-wetted surfaces. The degradation was followed by analysis of exposed stone, for Cl(-), SO4(2-) and NO3(-), and of run-off solution for Ca(2+). From these data, the total calcium released from limestone to reaction ions and products and the percentage of each pollutant reacted (and so the deposition velocity VD) were calculated. HCl acted independently of the presence of other pollutants, showed 40 and 100 % reaction (mass transport control) and VD values of 2.2 and 5.3 mm/s, at 84 % RH and on wetted surfaces. The reactivity of SO2 rose from 2.5 to 35 %, and VD from 1 to 2.9 mm/s, from conditions of 84 % RH to those with water, NO2 and O3. Similarly, the reactivity of NO2 rose from 3 to 40 % at 84 % RH in the presence of SO2 and O3, with a VD at 3 mm/s, but decreased in the presence of run-off solution. A limited study was performed on smoke-coated and naturally exposed, reaction-product-coated, samples. Non-wetted surface reaction products tended to reduce the attack of pollutants, but had no resisting effect when wetted.
The influence of combustion-derived pollutants on limestone deterioration: 1. The dry deposition of pollutant gases
This study concerns the relative chemical degradation effects of dry deposition of combustion-derived atmospheric pollutants, HCl, SO2 and NO2, on Portland and Monks park limestones, employing laboratory exposure chambers for periods of 30 days. Using presentation rates up to 40x10-10 g cm-2 s-1, the pollutants were assessed individually and in various combinations, along with ozone as oxidant, at 84 % RH with dry or water-wetted surfaces. The degradation was followed by analysis of exposed stone, for Cl(-), SO4(2-) and NO3(-), and of run-off solution for Ca(2+). From these data, the total calcium released from limestone to reaction ions and products and the percentage of each pollutant reacted (and so the deposition velocity VD) were calculated. HCl acted independently of the presence of other pollutants, showed 40 and 100 % reaction (mass transport control) and VD values of 2.2 and 5.3 mm/s, at 84 % RH and on wetted surfaces. The reactivity of SO2 rose from 2.5 to 35 %, and VD from 1 to 2.9 mm/s, from conditions of 84 % RH to those with water, NO2 and O3. Similarly, the reactivity of NO2 rose from 3 to 40 % at 84 % RH in the presence of SO2 and O3, with a VD at 3 mm/s, but decreased in the presence of run-off solution. A limited study was performed on smoke-coated and naturally exposed, reaction-product-coated, samples. Non-wetted surface reaction products tended to reduce the attack of pollutants, but had no resisting effect when wetted.
The influence of combustion-derived pollutants on limestone deterioration: 1. The dry deposition of pollutant gases
Einfluß der von Verbrennungsprozessen verursachten Schadstoffe auf die Zersetzung von Kalkstein: 1. Trockene Ablagerung der Schadstoffgase
Johnson, J.B. (Autor:in) / Montgomery, M. (Autor:in) / Thompson, G.E. (Autor:in) / Wood, G.C. (Autor:in) / Sage, P.W. (Autor:in) / Cooke, M.J. (Autor:in)
Corrosion Science ; 38 ; 105-131
1996
27 Seiten, 17 Tabellen, 52 Quellen
Aufsatz (Zeitschrift)
Englisch
| British Library Online Contents | 1996
| British Library Online Contents | 1996
Deterioration of mortar and concrete by pollutant gases
| British Library Conference Proceedings | 1996