Quantifying Decay Due to Wet Atmospheric Deposition on Basalt

Area of Science:

• Geosciences
• Materials Science
• Conservation Science

Background:

• Volcanic stones like basalt are understudied building materials crucial for heritage conservation.
• Wet atmospheric deposition poses a significant threat to the durability of stone-built heritage.

Purpose of the Study:

• To investigate the decay mechanisms of red basalt subjected to wet atmospheric deposition.
• To assess the suitability of water absorption capacity (WAC) and open porosity (OP) as decay monitoring variables.

Main Methods:

• Exposure of red basalt samples to artificial rain solutions simulating global, acid, and no-acid precipitation.
• Analysis of lixiviates to understand deterioration processes.
• Quantification of decay through mass difference, WAC, and OP measurements.

Main Results:

• The methodology effectively simulates accelerated weathering and decay.
• Red basalt is susceptible to decay via mineral dissolution, salt crystallization, cation exchange, and washing of compounds.
• WAC and OP changes are reliable indicators for monitoring in situ decay.
• Precipitation volume significantly impacts decay, more so than pH.

Conclusions:

• The developed methodology is suitable for studying the decay of building materials.
• Red basalt heritage is vulnerable to atmospheric wet deposition, with specific decay mechanisms identified.
• WAC and OP are promising variables for in situ monitoring of stone decay.