PURPOSES : The objective of this study is to develop a pavement rehabilitation decision tree considering current pavement condition by evaluating severity and distress types such as roughness, cracking and rutting. METHODS: To improve the proposed overall rehabilitation decision tree, current decision tree from Korea and decision trees from other countries were summarized and investigated. The problem when applying the current rehabilitation method obtained from the decision tree applied in Seoul was further analyzed. It was found that the current decision trees do not consider different distress characteristics such as crack type, road types and functions. Because of this, different distress values for IRI, crack rate and plastic deformation was added to the proposed decision tree to properly recommend appropriate pavement rehabilitation. Utilizing the 2017 Seoul pavement management system data and considering all factors as discussed, the proposed overall decision tree was revised and improved. RESULTS: In this study, the type of crack was included to the decision tree. Meanwhile current design thickness and special asphalt mixture were studied and improved to be applied on different pavement condition. In addition, the improved decision tree was incorporated with the Seoul asphalt overlay design program. In the case of Seoul's rehabilitation budget, rehabilitation budget can be optimized if a 25mm milling and overlay thickness is used. CONCLUSIONS: A practical and theoretical evaluation tool in pavement rehabilitation design was presented and proposed for Seoul City.

PURPOSES : The PMS(Pavement Management System) has been utilized in order to efficiently allocate the limited budget for the maintenance of national highway system. In the PMS of national highway, surface pavement condition is evaluated by using the VI (Visual Index). However, the VI is determined only by considering the cracking rate (%) and rut depth (mm), which is not reflecting the IRI (International Roughness Index) that is known as an important factor of pavement performance. In this study, the NHPCI (National Highway Pavement Condition Index) which includes the cracking rate (%), rut depth (mm), and IRI (m/km) is suggested for determining the rehabilitation methods group. METHODS : First, the rehabilitation methods performed between 2008 and 2010 on the national highway is classified and then, NHPCI is determined for each rehabilitation method. Next, the NHPCI for each rehabilitation method is grouped through the interval estimation of the population mean and T-test analysis. RESULTS : According to NHPCI range, the rehabilitation methods are divided into four categories: Not Required, Preventive Maintenance, Overlay Treatment (with or without cutting), and Full-scale Treatment (i.e., reconstruction). CONCLUSIONS : Based on this study, it is recommended that the appropriate NHPCI range should be determined through the combination of the rehabilitation categories and Decision Procedure of Pavement Distress Condition Visual Index.

현재 국도 PMS(Favement Management System)에서 적용하고 있는 보수공법결정체계는 소성변형과 균열의 기준치값에 대한 설정 근거가 명확하지 않다. 본 연구에서는 일반국도에서 아스팔트 콘크리트 포장의 보수 시 보수공법결정기준에 대한 근거를 제시하기 위한 것이다. 이를 위해 전국 일반국도 아스팔트 포장 구간을 대표할 수 있는 대표 구간을 선정하고, 포장전문가 패널(panel)을 선정하여 선정된 구간을 대상으로 패널이 대표구간을 평가하여 보수공법을 제안하였다. 포장전문가 패널이 대표구간을 평가한 결과를 분석하여 다음과 같이 보수공법 결정 기준의 근거를 마련하였다. 균열의 경우 절삭 덧씌우기를 요구하는 균열율은 35%, 덧씌우기 이상의 기준으로서 균열율 20%를 제안하였다. 소성변형의 경우 절삭 덧씌우기를 필요로 하는 소성변형 값은 13mm, 덧씌우기 이상을 요구하는 소성변형의 기준으로서 10mm를 사용할 것을 제안하였다.