ASSESSMENT OF CHROMATIC CHANGES DUE TO ARTIFICIAL AGING AND OR CONSERVATION TREATMENTS OF SANDSTONES/

Villamayor sandstone (also known as ''golden sandstone'') has been wid ely used for construction in the city of Salamanca since Roman times. In the present study, the four most characteristic varieties of this m aterial were used, considering the chromatic changes brought about by consolidation and/or waterproofing treatments and by cycles of artific ial ageing of natural stone and of stone subjected to these treatments . The treatments consisted of application of a consolidant at differen t concentrations (RC 70 and 40% RC 70) and two consolidants plus water proofing agents (RC SO and RC 90). Artificial ageing was induced by 10 cycles of wetting drying and freezing/thawing. The chromatic variatio ns observed considering the E, L*, a*, and b* parameters were subject ed to statistical analysis. (C) 1998 John Wiley & Sons.