Evaluating the physical properties and thermal comfort of vetiver adobe brick: a decade-long study on sustainable granary construction in Northeast Thailand

Contemporary architects emphasize eco-friendly and energy-efficient materials, yet many Thai farmers struggle with the high costs. Adobe brick, a sustainable material in northeast Thailand, is rarely used due to the lack of long-term performance data. This study aimed to enhance Vetiver adobe bricks by integrating traditional adobe techniques with conventional materials. Tests identified the optimal composition—earth, sand, lime, cement, and chopped Vetiver grass (5:3:1:1:4)—which outperformed other mixtures in maximum strength, porosity, moisture content, and water absorption. An experimental adobe granary was then constructed to assess its micro-environmental parameters, including temperature, humidity, and dew point. In January, April, and July 2014, comparisons were made between the Vetiver adobe granary at the Rice Research and Development Unit of Phu Phan Royal Development Study Center in northeastern Thailand and other granaries constructed with corrugated iron sheets and various materials in the neighboring village. Results indicated that the Vetiver adobe granary provided superior thermal comfort and effectively maintained a microenvironment for paddy preservation. A follow-up in 2024 revealed that adobe bricks exposed to natural ventilation for ten years retained similar physical properties, and the granary walls showed no significant weathering. The development of scientifically validated building materials that meet immediate agricultural requirements while establishing a replicable model for sustainable, community-based construction utilizing locally available resources. This integrated approach not only provides practical solutions for low-income housing but also contributes to creating a more sustainable and equitable built environment in Thailand and beyond.