Experimental investigation of thermal performance of metakaolin concrete in heat-exchanging walls using 1g physical modelling
Experimental investigation of thermal performance of metakaolin concrete in heat-exchanging walls using 1g physical modelling
The integration of Ground Source Heat Pump (GSHP) systems into retaining and foundation elements, known as Geothermal Energy Walls (GEWs), represents a sustainable approach to harnessing shallow geothermal energy for building heating and cooling. Despite the growing application of GEWs, the influence of thermally enhanced concrete materials on their heat exchange performance is not yet fully understood. This study experimentally investigates the thermal behavior of Retaining Geothermal Energy Walls (RGEWs) constructed with metakaolin-enhanced concrete using controlled 1g physical modeling. Two wall specimens, an Ordinary Concrete Wall (OCW) and a Metakaolin Concrete Wall (MCW), were tested under identical thermal loading conditions with a constant inlet temperature difference of 15°C. The results revealed that the incorporation of 10% metakaolin as a supplementary cementitious material improved both thermal conductivity and the system's overall heat transfer rate. The MCW exhibited approximately 8% higher soil temperature rise and a correspondingly greater heat penetration depth compared with the OCW, indicating enhanced effective thermal diffusivity and a greater capacity for near-field thermal diffusion. These findings highlight the dual benefits of metakaolin, which improves both mechanical strength and thermal performance, making it a promising additive for optimizing geotechnical structures integrated with GSHPs. The study provides benchmark data for validating future numerical simulations and supporting the development of design guidelines for next-generation thermo-active retaining systems.
M. Hajialilue-Bonab; Ali Khosravi; Emad Maleki Tabrizi; Salar Rahnema
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 5: Energy geo-structures and foundation systems
https://doi.org/10.53243/ICPMG2026-361