Investigation of the Effect of Discontinuity Functions on the Mechanical Performance of Treated and Untreated Asphalt Samples

Asphalt pavement cracking is an unavoidable phenomenon and the main factor of failure in pavement, which if followed, will lead to high costs and yet, with preventative measures, these costs can be reduced very effectively. Crack sealing is one of the preventive maintenance methods and the simplest and most economical way to repair recently cracked surfaces of asphalt pavement. This study was conducted to investigate the effect of discontinuity dimensions and their repair on the mechanical behavior of asphalt. Therefore, asphalt samples with treated and untreated discontinuities were made. Then dynamic creep, resilient modulus, fatigue, and durability testing were performed by the Lottman method on the samples. The results show that for a layer with finer granulation, sealing of narrow cracks (up to 20 mm wide) improves the corrosion resistance of asphalt concrete. Also, sealing cracks can increase the resistance of asphalt concrete to fatigue, regardless of the dimensions of the cracks. For a coarser-grained layer, sealing cracks deeper than width also reduces the resistance of asphalt concrete to sealing. Sealing cracks with overall width and depth of 20 mm reduces fatigue performance. Regarding resilience modulus for a layer with finer granulation and a layer with coarser granulation, crack sealing increases the modulus of resilience of asphalt concrete by 7.7% and 8.9%, respectively. The findings also indicate a more prominent role of discontinuity width than its depth on rutting behavior and durability. The results of this study are key in deciding the appropriate time to seal the cracks after their formation and improving some pavement properties in parallel with the treatment of cracks. Even though, generally, the desired effects of treatment on rutting, fatigue, and durability of pavements are partial and mostly negligible. However, sealing can be considered as a way to increase the resilient modulus of cracked pavements.