EFFECTIVESS OF USING GEOTEXTILES IN FLEXIBLE PAVEMENTS: LIFE-CYCLE COST ANALYSIS

Shih-Hsien Yang

Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in the partial fulfillment of the requirements for the degree of

Master of Science in Civil Engineering

Dr. Imad L Al-Qadi, Chair Dr. Gerardo W Flintsch Dr. Antonio A Trani

Feb 27, 2006 Blacksburg, Virginia

Keywords: Geotextile, Life Cycle Cost Analysis, Flexible Pavement, Cost Effectiveness, Agency Costs, User Costs

EFFECTIVESS OF USING GEOTEXTILES IN FLEXIBLE PAVEMENTS: LIFE-CYCLE COST ANALYSIS
Shih-Hsien Yang (ABSTRACT) 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. Two design methods were used to quantify the improvements of using geotextiles in pavements. One was developed at Virginia Tech by Al-Qadi in 1997, and the other was developed at Montana State University by Perkins in 2001. 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 low volume road design alternatives. A 50 year analysis cycle was used to compute the cost-effectiveness ratio when geotextiled is used for the design methods. The effects of three flexible pavement design parameters were evaluated; and their impact on the results was investigated. 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