Flexible Pavement Design Using MDP 2024 and Asphalt Institute

Abstract

Accurate flexible pavement thickness design is essential for structural reliability, particularly under high heavy-vehicle traffic and Over Dimension Over Load (ODOL) conditions that may accelerate fatigue cracking and rutting. This study compares pavement thickness, structural responses, and estimated service life obtained using the 2024 Pavement Design Manual (MDP 2024) and the Asphalt Institute method, supported by Pavement-PastDean, under three planned traffic-load scenarios of 5, 15, and 60 million CESA. The analysis uses actual field subgrade CBR data from Jalan Simpang Maruyung, Kutamandiri, Tanjungsari, Sumedang Regency, with a design CBR of 9%, selected from the lowest of three field measurements. Both methods produced pavement structures that met the design criteria in all scenarios. At 5 million CESA, the total thicknesses were 300 mm for MDP 2024 and 450 mm for the Asphalt Institute; at 15 million CESA, they were 385 mm and 505 mm, respectively; and at 60 million CESA, both converged to 540 mm. At 5 million CESA, estimated service life was 6.41 million CESA for MDP 2024 and 7.17 million CESA for the Asphalt Institute, while at 15 million CESA the values were 20.43 and 18.48 million CESA, respectively. At 60 million CESA, MDP 2024 produced an extreme value of 980,184.82 million CESA versus 79.35 million CESA for the Asphalt Institute. This extreme value is attributed to the transfer-function formulation after the AC-Base tensile strain decreased to 7.499 microstrain due to the stiff cement-treated base (CTB, E = 3,000 MPa), and should not be interpreted as evidence of superior rutting performance because both methods produced the same subgrade compressive strain. Overall, the relative performance of the two methods varied with traffic level, indicating a nonlinear relationship between load level and predicted pavement performance.