# Life-Cycle Cost Analysis on Application of Asphalt and Concrete Pavement Overlay
## 1 Introduction  
Concrete pavements account for approximately 62% of expressway pavements in Korea, out of which 9783 km (97.5%) comprise jointed plain concrete pavements and 189 km (2.5%) comprise continuously reinforced concrete pavements [1, 2, 3, 4]. The length of deteriorated concrete pavements that have exceeded the design life (20 years) was 1150 km in 2015 and 2605 km in 2020 and is expected to rapidly increase [5]. In the case of deteriorated concrete pavements, the application of sectional repair leads to an increased rate of early damage owing to the limited structural capability. Furthermore, the number of cases of repeated sectional repair is increasing. In Korea, it is difficult to extend the service life of deteriorated aged concrete pavements only with sectional repair; extensive reinforcement measures are urgently required [4, 5, 6]. In Korea, the maintenance cost for road pavements was approximately KRW 1.2 trillion in 2020, approximately three times higher than that in 2010, which was approximately KRW 0.4 trillion. The maintenance cost for expressways was approximately KRW 650 billion in 2020, which represented 54% of the total maintenance cost for road pavements. Therefore, to minimize the maintenance cost, it is essential to apply the appropriate maintenance to expressway pavements [5; 6; 7]. The method of maintenance for concrete pavements in Korean expressways is determined according to the maintenance standards. Owing to the structural limitations of deteriorated concrete pavements, the application of overlay is required rather than sectional repair. However, according to the maintenance standards for expressway concrete pavements, only 100% asphalt overlay is recommended, whereas concrete overlay is not considered [5]. asphalt overlay is preferred over concrete overlay because it requires lower construction cost, time, and curing period; thus, the traffic blocking time can be reduced. The cost of pavement construction encompasses the costs of construction equipment, material acquisition, design, maintenance and rehabilitation strategies, and operation throughout the service life [8]. The construction, maintenance, restoration, rehabilitation, and reconstruction of new roads, and the preservation of aged pavement, require enormous volumes of materials and nonrenewable energy sources, which exert excessive cost demands that impact the economy [9]. A life-cycle cost (LCC) analysis includes all the phases, starting from materials procurement, through design production, construction, maintenance, restoration, transportation, costs in the work zone, and recycling [10]. LCC analysis is a method based on principles of economic analysis that improves the estimation of the total long-term economic viability of different investment options and finds significant application in pavement management. The LCC analysis method finds significant application in pavement design and management [11; 12; 13]. LCC analysis has received increasing attention as a tool that facilitates decision making by transportation agencies toward beneficial economical investments [8]. In developed countries, for the design and maintenance of infrastructures highways, pavements LCC analysis is a reliable approach. The usage of LCC analysis is in selecting the least expensive pavement structure; the sustainability of the nation's highways can be enhanced by minimizing the life-cycle cost of pavements [14; 15; 16]. A detailed LCC analysis of concrete and asphalt roads revealed that concrete roads are 20% more economical than bituminous roads over a 30-year analysis period [17]. In Korea, many construction methods have been developed for concrete overlay through research. Visual inspection data on national highways in Korea were used and information about the road section and structural characteristics, location, number of lanes, average traffic (AADT), etc., was collected to estimate the parameters of the exponential hazard function [18].