U.S. Capitol - Marble
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Laboratory and in situ testing of the marble

A conditions survey was conducted followed by the development of materials and methods for repair and consolidation.

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Sculptural Pediments, East Front

ICR worked to conserve the Sculptural Pediments on the east front of the U.S. Capitol. ICR performed a preliminary survey of the pediments. Using historic documents and reports, changes since the last survey were noted. ICR formulated methods and materials for addressing the observed conditions. The benefits of potential consolidation treatments of both the Lee and marble with HCT (a consolidation treatment which has proven successful for use on calcium carbonate based stone) will be assessed. ICR treated representative marble samples and measured color change, alteration to water vapor transmission rate, change in strength and change in resistance to exposure to acid rain.

Exterior Marble

ICR assessed the exterior marble at the U.S. Capitol in order to determine whether the marble could be protected and strengthened in a manner that does not alter its historic character. A comprehensive conditions survey was conducted to document all conditions which might be improved by consolidation. ICR researched potential consolidation treatments to stabilize the weakened marble surfaces, increase soundness and improve resistance to acid rain, without sacrificing the original color, texture, sheen, or water vapor permeability of the original material. The testing program involved conducting a comprehensive laboratory and in-situ testing program of the potential consolidation treatments on the several varieties of extant exterior marble. Laboratory tests included petrography, freeze-thaw resistance, water vapor transmission rate testing, and indirect tensile strength evaluation.