Effectivess of Using Geotextiles in Flexible Pavements: Life-Cycle Cost Analysis
Using geotextiles in secondary roads to stabilize weak subgrades has been a well accepted practice over the past thirty years. However, from an economical point of view, a complete life cycle cost analysis (LCCA), which includes not only costs to agencies but also costs to users, is urgently needed to assess the benefits of using geotextile in secondary road flexible pavement.
In this study, a comprehensive life cycle cost analysis framework was developed and used to quantify the initial and the future cost of 25 representative design alternatives. A 50 year analysis cycle was used to compute the cost-effectiveness ratio for the design methods. Four flexible pavement design features were selected to test the degree of influence of the frame's variables. The analysis evaluated these variables and examined their impact on the results.
The study concludes that the cost effectiveness ratio from the two design methods shows that the lowest cost-effectiveness ratio using Al-Qadi's design method is 1.7 and the highest is 3.2. The average is 2.6. For Perkins' design method, the lowest value is 1.01 and the highest value is 5.7. The average is 2.1. The study also shows when user costs are considered, the greater TBR value may not result in the most effective life-cycle cost. Hence, for an optimum secondary road flexible pavement design with geotextile incorporated in the system, a life cycle cost analysis that includes user cost must be performed.