ANALYSIS OF THE DEGREE OF DEGRADATION OF BUILDING MATERIAL IN HISTORIC BUILDINGS USING NEAR INFRARED REFLECTANCE SPECTROSCOPY (NIRS)

This paper discusses the use of near infrared reflectance spectroscopy (NIRS) analysis for the characterization of materials and degradation processes in cultural heritage monuments, as an alternative to traditional laboratory methods, with the advantage of being a fast non-destructive process that requires little or no sample preparation, thereby reducing the amount of time required and the cost. NIRS is a spectroscopic method that uses the near infrared region of the electromagnetic spectrum (from similar to 800 to 2500nm). The technique can help to identify a chemical component from its different near IR absorption spectrum. In this study, the NIRS technique is applied to quantify constituents of stone material (calcite and quartz) and degradation indexes, by means of multivariate calibration techniques. These analyses provide immediate and highly accurate results about the levels of quartz and calcite in the stone material, cement and patinas from the church, obtaining good results.