ACL Project List

The terrazzo pavement at the New York State Pavilion was an innovation at the time of its production as it was the first project to incorporate glass and plastics. Material analysis of the pavement was important in selecting conservation treatments suitable to the properties of the materials themselves. Samples of the plain (grey) and colored terrazzo were analyzed using optical microscopy and X-ray diffraction and were found to have an aggregate/paste ratio of 70% / 30% in the plain terrazzo and 60% / 40% in the pigmented terrazzo. The blue and red tinted terrazzo both contained glass aggregate while the grey and other colored areas utilized the more traditional crushed stone.

Through chemical spot testing, it was found that the metal frame encasing the panel was tin-coated steel, while the dividers were made of tin-coated zinc. Tin-coated zinc strips held the plastic insets in place as well. The tin acted as an anti-corroding agent although tin itself corrodes rapidly in an alkali and acidic environment. Thin iron bars and iron mesh were embedded in the underbed for structural reinforcement.

The nature of the plastic insets was identified using Fourier Transform Infrared (FTIR) spectroscopy. The hand cut symbols and letters were made of polymethyl methacrylate, known under trade names such as Lucite or Plexiglas, which is produced in stiff sheets making it easier to cut. The linear plastic insets were made of cellulose acetate butyrate, known as Butyrate and preferred for its ease of formability in creating the curved contours represented in the map. These plastics have very different properties, including reactivity to various solvents. The identification of the plastic insets was essential in understanding their original selection based on inherent properties and in determining the appropriate treatments.