NCPTT’s Jason Church and Carol Chin presented research at the International Stone Congress on Wednesday, October 24. Church presented a comparative cleaning study for fragile marble monuments after pretreatment with hydroxyl conversion treatment. The purpose of this work was to develop a treatment methodology for the Arsenal and MaComb Monuments found in Congressional Cemetery, Washington, DCC.
He describes the preparation of surrogate samples to mimic the deterioration of Birkshire Lee marble similar to the composition of the monuments. Next he tested two possible stone consolidants, Prosoco OH100 and Prosoco HCT, to strengthen the fragile, soiled surfaces of the samples. Cleaning methods, including laser cleaning, chemical cleaning, and intermittent water misting, were then applied to the stone samples. Based on the results of testing, a treatment plan was developed using Prosoco HCT as a pre-cleaning consolidant. Church and others built a spray system around each monument and applied intermittent water misting. During the misting cycles, D2 biological solution was introduced. The results were successful.
Carol Chin presented a poster on the evaluation of cleaning methods and products for the removal of crude oil from stone. The work was based on investigations begun after the BP oil spill and subsequent oiling of Fort Livingston, Louisiana. Chin and others applied crude oil to samples of limestone, marble, and granite. Next the samples were artifically aged using a QUV weatherometer. Chemical cleaners were selected from the EPA national contingency plan and were applied to the samples. The researchers used color measurement, UV fluorescence, and contact angle goniometry to evaluate the effectiveness of the cleaners.