Alligator Cracking Performance and Life-Cycle Cost Analysis of Pavement Preservation Treatments

This memo describes work done to (1) develop performance estimates for pavement preservation treatments, and (2) estimate the cost-effectiveness in pavement preservation implementation. Construction project histories were collected from Caltrans, and their performance histories in terms of alligator cracking were extracted from the Pavement Condition Survey (PCS) database. The UCPRC-developed algorithm resolved the dynamic segmentation issue in the PCS data. Methodology on how to select adequate project data to use is documented. Median pavement lives to 10 percent and 25 percent Alligator B cracking for various flexible pavement treatments are estimated by means of a Kaplan-Meier estimator. Life-cycle cost analysis (LCCA) was performed with 20-year and 35-year analysis periods to try to determine (1) whether pavement preservation should be applied, (2) when pavement preservation should be applied. LCCA could only be completed for dense-graded asphalt overlays and chip seals with conventional binders due to limitations in complete datasets that could be gathered from existing Caltrans data sources. Cost differences were compared between continuous application of pavement preservation treatments or limiting these treatments to not more than twice in between rehabilitations. Findings from the LCCA show that, in general, (1) it is more cost-effective to apply pavement preservation treatment than to only rely on rehabilitation and (2) it is more cost-effective to apply pavement preservation at earlier stages of cracking rather than later. However, due to major limitations on the data that could be gathered for the analysis and despite the major effort by the UCPRC and by Caltrans HQ and Division of Maintenance staff, the results presented should only be considered as indications of pavement performance and life-cycle cost.