This study addresses the imperative for enhancing asphalt mixtures tailored for rural pavements, focusing on optimizing RAP mixtures with styrene–butadiene–styrene (SBS)-modified asphalt binders incorporating petroleum resin and oil. Through systematic investigation, the study examines the impact of varying RAP content (25% and 50%) and two SBS-modified asphalt binder types (Type 1 and Type 2) on mechanical properties and sustainability. Laboratory tests reveal that the mix of 25% RAP + 75% Type 1 exhibits exceptional flexibility, evidenced by a high ductility value of 880 mm at 25 °C, enhancing pavement resilience. Conversely, the 50% RAP + 50% Type 2 mixture displays vulnerability to fatigue cracking, while 25% RAP + 75% Type 1 demonstrates superior resistance, with a fatigue vulnerability value of 1524 kPa. The Hamburg Wheel Tracking test highlights the influence of RAP content on rut depth, with the mix of 50% RAP + 50% Type 1 achieving the lowest rutting at 3.9 mm. Overlay test results show the mix of 25% RAP + 75% Type 2’s resilience, with the lowest load reduction at 64.5%, while the mix of 50% RAP + 50% Type 1 exhibits substantial load reduction at 82.1%. Field tests unveil differences in pavement bearing capacities, with the mix of 25% RAP + 75% Type 2 demonstrating a remarkable elastic modulus of 58.5 MPa, indicating heightened bearing capacity. The investigation underscores the significant role of SBS-modified asphalt binders with incorporated petroleum resin and oil in enhancing fatigue resistance for sustainable rural pavements.

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.

Double bituminous surface treatment (DBST) has been a widely utilized pavement maintenance material due to its capability to restore the surface roughness of existing pavement and provide a layer of protection against weathering, aging, and moisture. However, DBST is highly prone to aggregate loss at an early stage, which is a very common problem experienced by surface treatment. Therefore, to lessen the aggregate loss and prolong the service life of DBST, fiber additive can be incorporated to strengthen the adhesion between the asphalt emulsion and aggregates. This study investigated the performance of glass fiber-reinforced polymer-modified DBST against aggregate loss by conducting laboratory tests using typical DBST as the benchmark of the test results. Four laboratory tests were chosen to represent different loading applications on the surface of the pavement: the bitumen bond strength (BBS) test, the sweep test, the Hamburg wheel-track test (HWT test), and a one-third-scale model mobile load simulator (MMLS3) model. Furthermore, the curing time of the asphalt emulsion was considered in the BBS test and sweep test. Based on all results from the conducted laboratory tests, polymer-modified DBST with glass fiber reinforcement presented an increased resistance to aggregate loss compared with typical DBST. Moreover, it was found that a longer curing time of the asphalt emulsion, whether it was typical or modified, strengthened the surface treatment’s resistance to aggregate loss.

If the production and construction information of asphalt mixture are tightly coupled and quality control is performed in real time, it is possible to minimize quality degradation and solve problems early. For these objectives, a cloud-based IoT (Internet of Things) PQMS (Pavement Quality Management System) was developed in this study. As a result, drivers and managers can monitor construction information and identify problems using monitors and apps. In 2023, it will be applied to national road construction sites to verify the effectiveness of the proposed cloud-based IoT PQMS and address potential problems.