Research on Local Heat Transfer Characteristics and Thermal Bridge Mitigation in UHPC Ribbed Sandwich Wall Panels

Concrete ribs， serving as crucial load-bearing components， inherently face thermal bridging issues that have become a core challenge in the energy-efficient design of such envelope systems. This study focuses on high-performance concrete ribbed sandwich insulation walls， employing three-dimensional steady-state heat transfer simulations to quantify the local thermal characteristics along the tangential （x）， normal （y）， and vertical （z） directions. The results indicated that the heat flux densities in the three directions exhibited an approximately proportional distribution. Structural geometric parameters primarily governed the proportional allocation of heat flow in each direction， while the thermophysical properties of materials determined the magnitude of increase. Based on this heat transfer behavior， a thermal bridge mitigation strategy was proposed， involving the differentiated wrapping of the ribs with aerogel felts in different directions. Optimal thermal performance was achieved when the ribs were wrapped with 16-mm-thick aerogel felts in the x and z directions， reducing the wall’s average thermal transmittance by 6.35% compared to the unwrapped condition. Under the same thickness of aerogel felts， this method reduced the wall’s average thermal transmittance by up to 20.28% compared to embedded local treatment， providing an effective approach for optimizing the thermal performance of concrete ribbed sandwich insulation walls.