Stone decay

G. G. Amoroso and V. Fassina, Stone Decay and Conservation, Materials Science Monograph 11, Elsevier, 1983. 

C. G. Amorosa and V. Eassina, Stone Decay and Conservation, Cleaning, Consolidation and Protection, Materials Science Monographs no. 11, Elsevier, Amsterdam, 1983. 

Quantitative data on stone decay seem rather scarce. Winkler [109] indicates that measurements of the rate of decay were made in Scotland by Sir Archibald Geikie [115] and in New York by Julien [116] in the 1880s and that work of this type was not resumed until after the Second World War. Fundamental knowledge of the kinetics and mechanisms is equally scarce a single paragraph in Winkler s book speculates about possibilities ranging from autocatalytic acceleration to retardation by transport across a product layer, i.e. the usual general topics of solid—gas kinetics, with no detail at all. There seems to be an important field for future work here and another in the matter of gas—solid interaction in the aerosol particles themselves. 

Amoroso, G. G. Fassina, V. "Stone Decay and Conservation" Materials Science Monographs No. 11, Elsevier New York, 1983. Livingston, R. A. Baer, N. S. Proc. 6th World Congr. on Air Quality, 1983. 

Figure 6 Damage function for stone. Stone decay proceeds, often at an assumed linear rate, to a critical threshold point. Beyond this point the damage is unacceptable. Unlike some phenomena to which this form of analysis has been applied, reducing pollution does not reverse the effects of damage. Certain suites of processes may operate at a more rapid rate to alter the stone, even under the same pollution conditions, than other suites of processes. This could result in differential damage on a building...

Figure 7 Stone decay and crusts on decorative arches at Portchester Castle associated with high counts of microorganisms...

Sulfur-oxidising bacteria convert inorganic sulfur compounds to sulfuric acid that can cause severe damage to mineral material. Thiobacillus species have been implicated with concrete corrosion in the Melbourne and Hamburg sewer systems due to sulfuric acid formation. However, a role in stone decay is less certain since sulfuric acid and calcium sulfate in stone can originate from the direct action of atmospheric pollution and acid rain. 

More damage to stone has occurred due to the corrosion of metallic bars than by any other mechanisms of stone decay. Fortunately, such bars are commonly present in structural units of the building and not in the sculptured regions where their effect would be even more serious. 

Stone preservation involves the use of chemical treatments that prolong the life of a stone, either by preventing or retarding the progress of stone decay or by restoring the physical integrity of the decayed stone (Bell and Coulthard, 1990). A stone preservative, therefore, may be defined as a material that, when applied, will avert or compensate for the harmful effects of time and the environment. When applied, the preservative must not change the natural appearance or architectural value of the stone to any appreciable extent. 

Fitzner, B. Heinrichs, K. Understanding and managing stone decay Prikiyl, R. Viles, H. A. Eds. The Karolinum Press Prage, 2002 pp. 11-56. 

Mcgreevy, J. P. Processes of urban stone decay Smith, B. J. Warke, P. A. Eds. Donhead Publishng. London, 1996 pp 150-167. 

Torfs, K., Van Grieken, R., 1997. Chemical relations between atmospheric aerosols deposition and stone decay layers on historic buildings at the Mediterranean coast. Atmos. Environ. 31, 2179-2192. 

Amoroso, G. G., Fassina, V. (1983). Stone decay and conservation Atmospheric pollution, cleaning, consolidation and protection. Elsevier. 

Price C.A. Stone-decay and preservation. Chem. Britain 1975 11(10) 350-353 Price C.A. Stone Conservation, An Overview Of Current Research. Los Angeles Getty Conservation Institute Publisher, 1996... 

Hammecker C (1995) The importance of the petrophysical properties and external factors in the stone decay on monuments. Pure Appl Geophys 145(2) 337-361. doi 10.1007/BF00880275 Hartog P, McKenzie P (2004) The effects of alkaline solutions on limestone. Discov Stone 3 34-49... 

BACKGROUND AND LOCAL CONTRIBUTIONS TO ACIDIC DEPOSITION AND THEIR RELATIVE IMPACT ON BUILDING STONE DECAY ... 

Northern Ireland thus provides a particular opportunity to study natural patterns and causes of building stone decay and also the impact of local pollution sources. To do this we examine in this paper first, the nature of rural and urban atmospheric pollution in Northern Ireland second, decay of sandstone buildings in Belfast together with the nature of associated particulate pollution and finally, decay associated with atmospheric pollution is compared to that caused by other agencies in both rural and urban environments. 

In view of these conditions it is understandable that building stone decay, especially of the traditionally dominant sandstones, is widespread and often severe within Belfast. As a consequence, cleaning and renovation of buildings has become equally widespread in recent years. Unfortunately, this work frequently progresses in the absence of a detailed knowledge of the nature and causes of local decay and, apart from... 

BUILDING STONE DECAY FIELD DATA COLLECTION FORM... 

Stone decay evident at City Hosp. to NW (Sst) Q.U.B. (Portland dressings to brick buildings + Sst) adjacent at E churches in general vicinity. 

Particulate deposition is important on buildings because it can produce xmsightly crusts as well as providing sites for sulphur oxidation. In assessing the role of particulates in stone decay, several environmental factors need to be taken into accoimt. These include the nature of the deposition as well as the frequency with which deposition events allow pollutants to interact with the material under examination. 

To date, nearly all exposure trials (eg. Sharp et al.. 1982 Ja)mes and Cooke, 1987) have provided information about the gross, averaged response of materials but say little about the actual surface response mechanisms. Additionally, although there is some agreement that particulates do contribute to building stone decay, it is not clear how important that role is whether some particles may be more important than others or how significant local factors are. Our investigations are a start in the assessment of these problems. 

It is difficult to assess what contribution local, regional or transnational pollution makes to stone decay in Portstewart, but the location and limited size of the town, together with its aspect which exposes it to Atlantic winds, argue against any major contribution. Instead, it would seem that the sometimes marked decay of sandstones, achieved over a relatively short time-span, is largely attributable to sea salts. 

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