Thermal conductivities under unsaturated condition and mechanical properties of cement-based grout for vertical ground-heat exchangers in Korea—A case study

摘要: Abstract In this study, the thermal conductivities of cement-based grouts for backfilling vertical ground-heat exchangers were investigated under saturated, air-dried and unsaturated conditions. The mechanical properties including p-wave velocity, elastic modulus Poisson’s ratio also measured. mix proportions applied quartzite sand/cement ratios 1, 1.5, 2, 2.5 3, with a fixed water/cement 0.7. Mixed-grout specimens prepared in both rectangular parallelepiped shape (11 cm × 6 cm × 4 cm) cylindrical (5 cm dia. × 10 cm height). Their decreased linearly decreasing degree saturation. Also, as was increased, conductivity at same saturation higher, more steeply decreased. Based on these results, an empirical equation representing relationship between derived. results obtained study are expected to be utilized input data behavior analyses their installations.