Weight losses of marble and limestone briquettes exposed to outdoor environment in the eastern United States: Results of exposure 1988--1992

摘要

Monitoring continued on weight changes in marble and limestone briquettes exposed to the outdoor environment at sites in the eastern US. This report presents data for the exposure period 1988--1992 and summarizes results for the entire period from 1984. Since 1989, only three exposure sites have remained active, but briquettes from preexposed material were added at those sites. A linear relationship was found between cumulative gravimetric losses and exposure period. These losses resulted in an average recession rate of 11 to 21 (micro)m/yr for marble and 21 to 45 (micro)m/yr for limestone. The recession rates are site-dependent and can be described with respect to rain depth and other atmospheric conditions, as evidenced by the very low rates at the Ohio site on the movable rack, dry regime. Weight monitoring is continuing in a planned 10-year program.