Early Thermodegradation of Bituminous Sealants Resulting from Improper Installation: Field Study

Bituminous sealants used in roadway maintenance often have a short effective service life, in great part as a result of improper installation and heating, in particular. To determine the effect of thermal history on sealant characteristics, sealant samples were collected during an operation that started with reheating of a full kettle of bituminous sealant. Results of Fourier transform infrared spectroscopy, thermogravimetry, gel permeation chromatography, and dynamic shear rheometry showed that the sealant had degraded and that the extent of degradation was greatest early in the operation. Application of degraded sealant throughout installation showed the need for improved material and construction specifications, along with improved field control measures.