For better optimization of pavement design and management, accelerated full-scale pavement tests (APT) represent very efficient tools to study pavement behaviour from initial to damaged condition. This paper presents an experimental study where three asphalt pavements with different interface conditions between the asphalt layers were tested in an APT experiment. Asphalt layer strains, FWD deflections, and surface cracking were monitored during the experiment. First, strain signals and pavement surface deflections measured at the beginning of the experiment, were used to characterize the viscoelastic properties of the asphalt layers. Then the measurements were used to analyze the fatigue behaviour of the experimental pavements, and the evolution of their level of damage to traffic. The analysis showed that in such asphalt pavements, asphalt strains, which varied significantly with the increase of load cycles, were not suitable for estimating an ‘average’ asphalt layer damage. In order to monitor the general pavement behaviour, a new damage ratio was introduced, based on FWD back-calculated moduli of the asphalt layers, that allowed to observe a stiffness increase of the asphalt layers at the beginning of the loading due to aging and post-compaction, and then fatigue damage evolution which had a very good correspondence with surface cracking.

T The roadway networks have been played a vital role in the development of all countries. The assessments of pavement conditions during their service life are therefore decisive to maintain the stable performance of the network. From this point of view, pavement instrumentation allows monitoring pavement conditions continuously and without traffic interruption. The study aims to illustrate the effectiveness of embedded strain gauges and temperature probes to follow the pavement responses with different traffic speeds, traffic loads and temperature conditions. The longitudinal strain signals are then examined with regards to representative parameters of the loading times and strain amplitude. The results show that the traffic load levels and asphalt temperature are directly responsible for the change of strain amplitudes, while those have almost no impact on loading times. Numerical simulations are also introduced to validate the applicability of both layered elastic and viscoelastic models to the strain signals observed in the field.

Road traffic accidents (RTAs) remain a pressing global issue, particularly in Southeast Asia, including Vietnam, where the severity of crash outcomes poses a major challenge. This study analyses and models the severity of RTAs on Vietnam’s expressway network over a 7-year period, compiling a dataset of 491 crashes that include key accident characteristics, roadway features and vehicle involvement patterns. Critical trends were identified, such as the higher occurrence of accidents on expressways with elevated speed limits, the significant role of truck- and coach-related RTAs and the direct influence of infrastructure elements like median barriers and emergency lanes on crash severity. Using the Random Forest (RF) model, the study identified key predictors of severity—including vehicle type, collision type, speed limits and lane count—and compared its performance with XGBoost and SVM. RF achieved the best overall predictive accuracy, while partial dependence plots (PDPs) were applied to interpret how major factors affect severity outcomes. The findings provide evidence for traffic safety policy, supporting stricter regulation of high-risk vehicles; targeted enforcement, infrastructure upgrades and context-specific interventions based on time and environmental conditions are essential to mitigate the consequences of crashes and reduce the severity of injuries and fatalities. Future work should establish a standardized national crash database with detailed behavioural and environmental factors, explore advanced machine learning (ML) methods when larger datasets are available and validate the model across diverse regions and road types.

Tạp chí Khoa học Giao thông vận tải - Trường Đại học Giao thông vận tải;Transport and Communications Science Journal under University of Transport and Communications was established in 2002 and launched online version in 2019.

Transport infrastructure is a critical component of socio-economic development, particularly in rapidly urbanizing Vietnam, where increasing traffic congestion poses significant challenges. Road surface quality and durability are essential factors in ensuring the efficiency and longevity of the transportation system. Carboncor Asphalt (CA) material, with its superior resistance to cracking, water damage, and harsh weather conditions, is a promising solution for road surface construction in Vietnam. However, there is a limitation of research on the mechanical behavior of carboncor asphalt in the specific climatic and environmental conditions of the country. To address this knowledge gap, this study investigates the shear behavior of a carboncor asphalt layer interfaced with both asphalt concrete and cement concrete surface layers. A comprehensive range of laboratory tests is conducted to assess the bond strength between the carboncor asphalt layer and the overlying road surfaces. Results indicate a negative correlation between temperature and bond strength for the overlay carboncor asphalt layer on both asphalt and cement concrete substrates. Notably, bond strength demonstrated a significant increase over time. The findings in this study are expected to have significant implications for road construction and maintenance using CA overlay in Vietnam. By providing a scientific foundation for material selection, design, and construction of road surfaces tailored to local conditions, this study aims to enhance investment efficiency and reduce maintenance costs