Bio-Fog Seal Evaluation

Project summary:

Pavement preservation is playing an increasingly significant role in maintaining aging pavement infrastructure. One important component is the application of sealants to the pavement surface. In a joint study between the Minnesota Department of Transportation (MnDOT) and the University of Minnesota, the field performance and mechanical properties of asphalt mixtures from pavement sections treated with a number of new products--called bio sealants--was investigated. The objective of the study was to obtain relevant properties of treated asphalt materials in order to understand the mechanism by which sealants improve pavement performance. Laboratory testing was performed on treated asphalt binder and mixtures. For binders, a dynamic shear rheometer and a bending beam rheometer were used to obtain rheological properties of treated and untreated asphalt binders. Field cores from both untreated and treated sections were collected and thin beam specimens were prepared from the cores to compare the creep and strength properties of field-treated and laboratory-treated asphalt mixture. It was observed that the oil-based sealants have a significant softening effect on the control binder compared to the water-based sealants. For asphalt mixtures, different trends were observed for the field samples compared to the laboratory-prepared samples. Similar to binder results, significant differences were observed between the asphalt mixtures treated with oil-based and water-based sealants, respectively. From the analysis performed on the bending creep and strength results at low temperature, it was concluded that the application of sealants in the field have no significant effect on these properties. Fourier transform infrared spectroscopy (FTIR) analysis showed that the sealant products could not be detected in mixture samples collected from the surface of the treated section.