Chiang Mai Journal of Science

     In this study, the perlite-based insulating material is developed to meet ASTM C610 standards in a form of the board. Expanded perlite powders with a tapped density of 53 and 150 kg/m³ were used in this study. Sodium silicate used as a proper binder at various concentrations was mixed with perlite powders. The homogeneous moist mixture was formed by uniaxial pressing at different compaction ratios. Specimens were dried at low temperatures (250-400°C). Measurements of physical properties e.g., flexural strength, bulk density and thermal conductivity, were conducted. Perlite foam was set after drying, leading to an increase in its moisture resistance and strength. Compression molding also affected the density and strength of the products. Heat treatment after forming was carried out in order to dehydrate water molecules and bond particles together. The specimens were tested in accordance with ASTM C610 as a result of optimum conditions from perlite powder with a tapped density of 53 kg/m³. Perlite foam board had been successfully fabricated with a bulk density of 205 kg/m³, flexural strength of 434 kPa, compressive strength of 764 kPa and room temperature thermal conductivity of 0.056 W/m.K.