This research investigates the possibility of using high-density polyethylene (HDPE) plastic waste to improve the properties of asphalt concrete pavement. HDPE plastic waste contents of 1, 3, 5, and 7% by aggregate weight were used. HDPE plastic waste=stabilized asphalt concrete pavement (HDPE-ACP) was evaluated by performance testing for stability, indirect tensile strength, resilient modulus (MR), and indirect tensile fatigue (ITF). In addition, microstructure, pavement age, and CO₂ emissions savings analyses were conducted. The performance test results of the HDPE-ACP were better than those without HDPE plastic waste. The optimum HDPE plastic waste content was 5%, offering the maximum MR, ITF, and pavement age. Scanning electron microscope images showed that the excessive HDPE plastic waste content of 7% caused a surface rupture of the sample. Improvements in the pavement age of the HDPE-ACP samples were observed compared with the samples with no HDPE plastic waste. The highest pavement age of the HDPE-ACP sample was found at an HDPE plastic waste content of 5% by aggregate weight. The CO₂ emissions savings of the sample was 67.85 kg CO₂-e/m³ at the optimum HDPE plastic waste content.

This research investigated the unit weight and unconfined compressive strength (UCS) of cellular lightweight high-calcium fly ash geopolymer and cement-stabilized soft Bangkok clay (CLFAG-OPC stabilized SC) as potential lightweight embankments and backfill materials. The investigated parameters included the soft clay:fly ash (SC:FA) ratio (50:50 to 90:10), ordinary Portland cement (OPC) content (0%-3%), water content (1.5LL-3.0LL), liquid alkaline content (L) (0.6FA to 1.5FA), NS:NH ratio (0.5-3), NH concentration (8 M), air foam content (Ac) (0%-150% by SC volume), and curing time (7-90 days). The results indicated that the SC:FA ratio, OPC content, water content, NS:NH ratio, L content, and Ac significantly influenced both the unit weight and UCS of samples. Increasing water content, L content, and Ac generally reduced unit weight, except when influenced by FA content, OPC content, and the NS:NH ratio. The optimal composition for maximum UCS was achieved with an SC:FA ratio of 50:50, OPC content of 3%, water content of 2.0LL, NS:NH ratio of 1, L content of 0.6FA, and 0% Ac. A predictive equation for unit weight was proposed using phase diagrams. Additionally, mix design charts were shown to be valuable tools for calculating the unit weight and UCS, demonstrating their effectiveness for lightweight embankment and backfill applications.

This research studied the relationships of indicators related to the selection of intercity train services in Thailand’s Nakhon Ratchasima province. The goal was to examine the characteristics of the intercity train services and the factors that influence choosing them. The research tool used to collect data consisted of 508 sets of questionnaires completed by samples who had used the intercity train service. The data were analyzed using structural equation modeling to investigate the service quality and customer satisfaction indicators affecting the selection of intercity train services. The study found that the service quality indicators included station, service, staff, and vehicle. The customer satisfaction indicators included station, service, travel promotions, and price satisfaction. However, when the service quality indicators were investigated, they had a direct positive effect on customer satisfaction at the 0.01 level of statistical significance. Passengers are most satisfied with obtaining travel information, such as train timetables, fares, and updated information. The involved agencies can use the study’s findings to determine policies and formulate plans for information management and intercity train service metrics.

The expansion of the transport sector in Thailand has resulted in a continuous increase in greenhouse gas emissions and air pollution. Therefore, promoting the adoption of commercial electric vehicles (EVs) has become an important approach to mitigating environmental impacts and enhancing sustainability. This study integrates the TAM, TPB, and 7Ps frameworks to examine factors influencing the intention to adopt EVs among freight transport operators in Thailand. A total of 876 freight operators were surveyed, and the data were analyzed using a random parameters probit model with heterogeneity in means. The results indicate that environmental motivation, perceived safety, ease of use, reductions in operational costs, social benefits, dealership credibility, and perceived quality-of-life improvement positively influence the intention to adopt EVs. In contrast, gaps between EV attitudes and purchasing readiness, along with over-reliance on promotional and online channels, negatively affect EV adoption intention. Furthermore, perceptions of price appropriateness show heterogeneous effects across respondents, reflecting hidden costs and operational uncertainties. Based on these findings, the study proposes an integrated set of policy measures to support a sustainable transition toward EV adoption in the freight transport sector. These results provide useful guidance for policymakers and freight transport operators in developing strategies and policies that encourage the long-term adoption of electric vehicles in freight transportation.