Performance Evaluation on the Application of MAST and RCC on a Cambodian Rural Road: A Case Study

Cambodia’s transportation sector has exhibited tremendous growth in the past decades together with its economic advancement. However, these improvements are only focused on the national and provincial roads, leaving the rural roads underdeveloped. A large percentage of the rural roads in Cambodia are unpaved while those paved roads are in deteriorated condition, making these rural roads prone to structural failure when subjected to heavy truck traffic and massive rainfall. Therefore, an innovative pavement material shall be used in the construction and rehabilitation of Cambodian rural roads. In this study, a composite pavement testbed consisting of a roller compacted cement (RCC) base layer and a modified double bituminous surface treatment (DBST), namely multi-layered bituminous surface treatment (MAST), was constructed in Cambodia and its performance was evaluated. To have a point of comparison, the testbed was divided into three sections with varying combinations of surface and base layer: (1) MAST surface with an RCC base, (2) MAST surface with an aggregate base, and (3) DBST surface with an aggregate base. Initially, a visual inspection was conducted to investigate the surface condition of the testbed. To assess the structural capacity, a light-falling weight deflectometer device was used. Meanwhile, the surface roughness was evaluated through the sand patch test. Lastly, the pass-by test was performed to quantify the noise level of the pavement. Based on the results, the proposed composite pavement performed significantly superior to the typical pavement in Cambodia, which is the third section. In summary, the composite pavement with MAST as the surface layer and RCC as the base layer was observed to be suitable for heavy truck traffic loading and the environmental conditions of Cambodia.