Evaluation of the self-healing performance of polyurethane-modified bitumen using bitumen bond strength (BBS) test and CT scan

Abstract

Upgrading the self-healing property of bituminous mixtures is of great importance to extend the pavement service life and road safety with fewer maintenance treatments. The objective of this paper is to investigate the effect of bitumen modification with different percentages of toluene diisocyanate (TDI-Co) polyurethane polymer on the healing property using bitumen bond strength (BBS) test. Moreover, the effects of factors such as temperature and rest period duration were also investigated at three different temperatures (25, 35, and 45°C) and during 6 or 24 hours rest periods. Besides, to evaluate the accuracy of the measured healing values, samples were CT scanned at 25 °C. It was concluded that the use of polyurethane polymer increased the self-healing performance of the bitumen and increasing the polymer content, has intensified this improvement. It was also found that higher temperatures, as well as healing time extension, increase the healing rate and healing performance of modified bitumen. Following the findings from the BBS test, CT scanned images also showed that the healing rate is negligible at 25°C, and there is no change in large cracks.