Identification of impact damage to flexible pavement under cyclic loading on soft clayey soil

Abstract

The object of this study is the behavior of flexible pavement built on soft clay subgrade from Karawang, Indonesia. The problem to be solved is the identify the response the subgrade to repeated loads with different moisture content and speeds, representative of dynamic loads from vehicle movement. Soft clay is one of the problematic soils. Low bearing capacity, low permeability and high ability to absorb water are the causes. Using flexible pavements that built on soft clay subbases often fail early because of the repeated loads from traffic and the weakening of soil strength due to moisture. A laboratory pavement model, scaled at 1:20, was created to simulate road loading. The moisture content of the subbase varied at 0%, 19%, 36%, and 53%. Loading speeds were set at 4.3 cm/s and 8.6 cm/s, with each load repeated 200 times to measure stress and deformation in the clay soil subbase. Besides identified the soft soil subgrade response, the analyzed for its physical, mechanical, and mineral content, including Atterberg limits, permeability, and X-ray diffraction (XRD). The results indicate that higher moisture levels consistently increase stress in the subbase and underlying layers due to lower effective stress and reduced soil stiffness. In As-G/3 stress ranges from 0.005 to 0.013 με and in As-G/5 stress ranges from 0.005 to 0.011 με. Deformation behavior depended greatly on layer position, moisture level, and loading speed. The most significant deformation occurred in the deeper pavement layers (As-C/6 and As-G/6), particularly at 53% moisture, which showed a major loss of stiffness and a greater likelihood of permanent deformations. The maximum values of 0.75 με and 0.35 με, Moisture level emerged as the key factor affecting stress distribution and deformation in flexible pavements on soft clay. The findings highlight how moisture and speed can greatly impact flexible pavement performance and must be considered in road design and upkeep to avoid track failure and early structural failure