Deterministic and probabilistic life-cycle cost analysis of pavement overlays with different pre-overlay conditions

Abstract

This study aims to evaluate the effect of pre-overlay condition on pavement performance and develop deterministic and probabilistic approaches to analyse the cost-effectiveness of pavement overlay alternatives. Pavement-condition data collected from Pavement Management System were used to analyse the service life of pavement overlay with different pre-overlay conditions and overlay thicknesses. Deterministic and probabilistic life-cycle cost analysis (LCCA) was first conducted to compare life-cycle cost (LCC) of different overlay treatments. Statistical test proves that the estimated overlay life for major rehabilitation is significantly higher than the overlay life for minor rehabilitation. Deterministic LCCA results show that there is a threshold of pre-overlay surface distress index (SDI) where the LCC is equal between major and minor rehabilitation treatments. Sensitivity analyses show that the cost ratio between major and minor rehabilitation treatments has significant influence on the threshold of SDI. Probabilistic LCCA results demonstrate the possible variations of LCC for different rehabilitation treatments. A probability index is proposed to quantify the probability that the LCC of minor rehabilitation is greater than the LCC of major rehabilitation. The analysis results show that probability index decreases as the pre-overlay SDI value increases or the cost ratio between major and minor rehabilitation treatments increases. The cost-effectiveness of rehabilitation treatments can be analysed using the LCCA approach developed in this study considering different pavement performance indicators and analysis parameters.