Image Processing Method to Estimate the Wearing Condition of Slurry Seal Mixtures

Abstract

Slurry seal surfacing is a preventive pavement maintenance method to correct surface erosion and irregularities, fill the cracks, and improve the skid resistance. Slurry seal can increase the efficient life of asphalt pavements with a low initial cost. One of the most important parameters affecting performance of a slurry seal is the percent of abrasion (aggregate and bitumen loss) over the service life of the layer. This study investigates the wearing performance of slurry seal mixes using an image processing technique. Performance of various slurry seal mixtures made with virgin and RAP aggregates were evaluated using wet track abrasion test (WTAT). WTAT samples were image analyzed to see the effects of large aggregate, bitumen, and small aggregate loss. High-resolution images were taken from WTAT samples before and after the abrasion test. Applying proper filters and thresholds, images were converted to the binary format to distinguish two material phases, i.e., aggregate and bitumen. After image processing, two loss parameters were compared with the results of wear values. The results showed that bitumen loss and large aggregate loss are the driving factors for abrasion of virgin slurry seals and RAP slurry seal, respectively in its initial service life. It is crucial to use compatible emulsion bitumen and aggregate material for both the virgin and RAP slurry seals. RAP slurry seals should be lightly rolled after lay-down to improve the friction life and the aggregates embedment into the slurry seal mat.