Abstract
This study presents a Life Cycle Cost Analysis (LCCA) of the Abuja-Keffi Expressway, focusing on the Mararaba axis, to evaluate and compare the economic implications of two flexible pavement options: asphalt pavement and soil pavement. The research is motivated by the economic challenges faced by road engineers and contractors in Nigeria due to poor road conditions and the associated high maintenance costs. The study employs RealCost 3.0 software and follows a 35-year evaluation period methodology to account for all life cycle costs, including construction, maintenance, and user costs. The analysis considers design alternatives, agency costs, user costs, maintenance costs, and discount rates. The specific area of focus is the Abuja-Keffi Road, a critical link between northern and southern Nigeria. The study presents a Life Cycle Cost Analysis (LCCA) comparing two pavement alternatives, Asphalt Pavement (Alternative 1) and Surface Dressing Pavement (Alternative 2), focusing on key financial metrics such as the Undiscounted Sum, Net Present Value (NPV), and Equivalent Uniform Annual Cost (EUAC). The Undiscounted Sum, representing total expenses over the project's lifespan, reveals that Alternative 1 incurs $1,170,436.88/ ₦925,825,091.28, while Alternative 2 costs $441,433.94/₦348,878,774.54. Considering the time value of money, NPV is higher for Alternative 1 at $1,136,191.38/ ₦896,236,417.58, compared to $413,271.56/₦326,795,499.75 for Alternative 2. The EUAC, indicating uniform annual costs equivalent to NPV, is $41,060.38/ ₦32,476,199.78 for Alternative 1 and $14,935.06/₦11,793,070.46 for Alternative 2. Despite Alternative 1's higher NPV, the significantly lower EUAC for Alternative 2 implies lower annual costs, emphasizing the importance of considering the breakdown between agency and user costs in decision-making. A higher NPV signals a financially attractive investment, while a lower NPV may suggest less economic viability, especially when factoring in the time value of money. In conclusion, the study recommends proper design and construction of drainage systems to reduce flooding, regular maintenance to extend pavement life, quality control in construction, and consideration of local conditions in pavement selection. The LCCA results highlight the economic benefits of asphalt pavement in the long term, considering durability and performance.

Key words: Transportation Infrastructure, Asphalt Pavement, Surface Dressing Pavement, Cost Analysis, Life Cycle Cost Analysis (LCCA).