Survival Analysis and Cost Effectiveness of Winter Pothole Patching Techniques

Abstract

The main objective of this study was to perform survival life analysis and life-cycle cost analysis of different patching methods and materials commonly used for winter pothole maintenance. To this end, a comprehensive testing matrix was developed that included the installation of 356 pothole patches on different types of roads using four different patching techniques with five commonly used patching materials. The patching techniques included spray injection and three types of throw and roll methods using a tamper, a truck tire, or a vibratory roller. The results of the field-testing program indicated that throw and roll with a tamper had the highest productivity, followed by throw and roll with a truck tire and throw and roll with a roller. Spray injection had the lowest productivity. The result of the classification tree model indicated that patching method is the most significant factor affecting the patching performance, followed by patching materials, traffic volume level, pothole size, and number of days to experience first snowfall after installation. In addition, the results of hazard risk analysis indicated that the patching method, materials, size of the pothole, and traffic volume level were statistically significant for the survival life of pothole patches. Survival analysis results indicated that patches installed with throw and roll with a roller and spray injection had a relatively longer survival life than that of throw and roll with a tamper or a truck tire. However, the results also depicted that the survival life of the patches installed with the latter two methods can be satisfactorily longer if a cold mix of good quality is used. The level of compaction was found to be significantly important in the survival life of hot-mix asphalt. In general, throw and roll with a tamper or a truck tire were found to be the most cost effective in both the short and long term, especially on streets with low traffic volumes. However, in the case of heavy/medium traffic volumes, spray injection and throw and roll with a roller could be more cost-effective, especially if the agencies are looking for long-lasting solutions.