A Preliminary Analysis on Determination of Optimum Crack Sealing Time for Asphalt Pavement

Crack is one of the major causes of failure in asphalt pavements, and it also accelerates the severity of other distresses. Crack sealing is one of the main methods of preventive maintenance. However, until now, there has no standard procedure based on rigorous scientific approach to determine the best sealing time of the cracks. Therefore, this study aimed to establish a preliminary crack opening model for northeast region of China. Generally, it is found that the absolute change value for crack width in one year is much higher than that in one day. Therefore the following preliminary crack opening model was built based on the year round observation data for unsealed asphalt pavement. The 20×20 mm square reservoirs for crack sealing was selected to discuss the effect of sealing time on the crack sealing performance. The approximate analysis has shown that the unreasonable sealing time will induce the premature failure for sealant and sealant-crack system. Especially, at low temperature, the sealant needs to have a good ductility to prevent the fracture itself. Finally, a polynomial function was proposed to describe the crack opening distance. The model was then used to preliminary determine the appropriated crack sealing timing of the year. It is recommended to select the average temperature between the two inflexions in polynomial function as the sealing temperature, and the corresponding time as the sealing time. It is also noticed that this time varies for different regions.