Sustainability-oriented construction materials for traditional residential buildings: From material characteristics to environmental suitability

The increasing replacement of traditional construction materials with modern alternatives often overlooks their superior environmental adaptability and sustainability, resulting in missed opportunities for energy efficiency and carbon emission reductions. This study aimed to address this issue by scientifically evaluating the material properties of volcanic rock from Hainan Island, China, to assess its potential for sustainable building practices in tropical climates. A series of material characterization techniques were employed to analyze the composition and structure of the volcanic rock, including optical profilometry (OP), polarized light microscopy (PLM), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) with energydispersive spectroscopy (EDS), transient plane source technique (TPS), and mercury intrusion porosimetry (MIP). Our findings identified the rock as vesicular cryptocrystalline basalt, with its unique pore structure and mineral composition jointly contributing to a low thermal conductivity of 0.22 +/- 0.04 W/(m & sdot;K). The pore structure was characterized by closed spherical cavities, needle-like lava fillings, nanoporous surfaces, complex pore-throat networks, and an extensive pore size distribution. These features significantly reduced gas convection and enhanced thermal resistance. Additionally, the rock composition, dominated by the amorphous volcanic glass and scattered hollow skeletal crystalline plagioclase, further diminished heat transfer. These characteristics indicated that Hainan volcanic rock possessed excellent thermal insulation properties, making it highly suitable for energy-efficient construction in hot climates. This study highlighted the potential for traditional materials like volcanic rock to contribute to sustainable building practices and the preservation of cultural heritage.