Mechanical and thermal performance of hollow glass microsphere-reinforced earthen masonry walls in severe cold regions

Abstract

This study investigates the mechanical and thermal performance of hollow glass microsphere- and jute fibre-stabilised earthen masonry walls for structural building envelopes in severe cold regions. Raw soil from Xiwusutu Village, Hohhot, was stabilised with 6 wt% hollow glass microspheres (HGMs), 14 wt% ordinary Portland cement and 0.8 wt% jute fibres. Four block configurations, including solid full-size, solid half-size, hollow full-size and hollow half-size earthen blocks, were fabricated by pneumatic compaction. The modified blocks achieved compressive strengths of 4.83–8.27 MPa, corresponding to increases of 23.5%–111.5% compared with untreated controls and 169.8%–362.0% compared with traditional local earthen blocks. Environmental chamber tests under a steady 28 °C temperature difference showed that the heat transfer coefficient decreased from 1.446 W/(m²·K) for the solid wall to 1.118 W/(m²·K) for the hollow wall, while the equivalent thermal conductivity was reduced by 27.4%. A validated COMSOL Multiphysics model was used to optimise the external XPS insulation thickness from 10 mm to 60 mm. The hollow wall satisfied the severe cold zone limit of 0.50 W/(m²·K) with a 20 mm XPS layer, whereas the solid wall required 30 mm. These results demonstrate that material stabilisation, hollow block geometry and external insulation can provide a balanced structural-envelope solution with sufficient compressive capacity, reduced self-weight and improved thermal performance for low-rise earthen masonry buildings in severe cold regions.