The purpose of this study was to optimize the design of asphalt concrete pavements for Jeju Island by considering the regional characteristics of the island. This study employed an MEPDG program to determine the allowable traffic loads for class 4 vehicles by considering the axle loads, climate, and material properties. Samples of basalt asphalt concrete from Jeju were used to measure the dynamic modulus for material property estimation. The climate input was based on 30-year climate data from Jeju. The thicknesses and moduli of the subgrade, subbase, and asphalt layers were incorporated into the design. The regression-analysis program SPSS was used to develop a regression equation for the overlay design, factoring in the modulus and thickness ratios between the existing and overlay asphalt layers. A pavement-thickness design formula tailored to Jeju's characteristics was derived. An equivalent single-axle load factor (ESALF) formula was developed to facilitate traffic-load estimation for different roads, enabling the easy incorporation of varying traffic volumes into the design. The ESALF formula demonstrated a high correlation with the pavement thickness, subgrade conditions, and axle loads, whereas the pavementthickness design formula exhibited strong correlations with the pavement thickness, subgrade state, thickness ratios, and modulus ratios. The use of basalt aggregates in asphalt concrete pavements provides an economically viable and technically sound solution for Jeju. The proposed design methodology not only reduces costs but also enhances pavement performance and road safety. The developed formulas offer flexibility in adjusting designs based on specific traffic conditions, providing optimal pavement solutions for different road categories.

PURPOSES : In this study, the basis for improving the maintenance method of road pavement in Jeju Island, where deterioration is accelerating, was presented through field construction and analysis of various combinations of maintenance methods. METHODS : Construction was performed on Jeju Island's Aejo Road, which has high traffic and frequent early damage, using various asphalt mixtures mainly applied in Jeju Island, with different maintenance cross-sections depending on the level of repair. The quality and performance of the asphalt mixture collected during construction were evaluated, and MEPDG was used to analyze the service life according to the type and maintenance level of the mixture. RESULTS : While the mixture for the surface layer satisfied the quality standards and had excellent rutting and moisture resistance performance, the asphalt mixture for the intermediate and base layer did not satisfy the quality standards such as air voids, so it was judged that quality control was necessary during production. The section repaired to the base layer was found to be advantageous for the integrated behavior of the pavement and had the best structural integrity. As a result of predicting the service life, the estimated life of the section where only the surface layer was repaired was analyzed to be approximately 7 years, the section where the intermediate layer was repaired was 14.5 years, and the section where the entire section up to the base layer was repaired was analyzed to be 18 years. CONCLUSIONS : In Jeju Island, where deterioration is accelerating, it was analyzed that when establishing a maintenance plan, it is necessary to consider repairing the middle and base floors in order to secure the designed life of 10 years.

PURPOSES : The purpose of this study is to evaluate an asphalt mixture via field application to utilize basalt aggregates produced on Jeju Island for a warm mix asphalt (WMA). METHODS : Using commercially available WMA additives, an indoor experiment is conducted on low- and high-void aggregates among basalt aggregates on Jeju Island. The physical properties of the WMA mixture are evaluated using one solid type and two liquid types of WMA additive. To evaluate the applicability of the WMA additives, air void, saturation, aggregate void, Marshall stability, flow number, indirect tensile strength, and toughness tests are performed. For the field application of WMA using basalt aggregates, three types of pavements (HMA, WMA-Solid, and WMA-liquid) are constructed. When applying the pavements in the field, an anti-stripping agent is incorporated to improve the water resistance while considering the characteristics of the basalt aggregate. Samples are acquired via plant and field coring to evaluate the properties of the materials applied in the field. RESULTS : In the indoor test for analyzing the applicability of the commercialized WMA additives to basalt aggregates, all tests except the indirect tensile strength test show results that satisfy the standards. All test results, including that from the indirect tensile strength test, satisfy the standard values in the test that uses the sample material obtained from the plant. Similarly, in the test with field cores, all test results satisfy the standard values. Therefore, the experimental value in the field application is generally higher than the test value in the indoor experiment. It is inferred that this is due to the difference between the basalt aggregates used in the indoor and field experiments, as well as the addition of the anti-stripping agent. CONCLUSIONS : Basalt aggregates produced on Jeju Island can be used for WMA pavements, as demonstrated via indoor experiments and field applications. However, owing to the characteristics of basalt aggregates, a method for improving water resistance should be considered, and tests to determine the indirect tensile strength should be performed using various basalt aggregates. In addition, because various basalt aggregates exist owing to the diverse geology characteristics of Jeju Island, they should be evaluated via more experiments and field applications.