The Potential of Sand as a Sustainable Infill for 3D Concrete Printed Building Walls (2025-03)¶

Three-dimensional concrete printing (3DCP) is an emerging construction technology offering significant potential to revolutionize the building industry through the digital fabrication of freeform structural components. However, current wall assembly designs adapted from traditional construction often incorporate interior air cavities that can introduce heat loss challenges during the highly integrated 3D printing process. This study presents preliminary findings from ongoing research exploring sand as an alternative cavity infill material, which offers potential solutions to these challenges while enhancing overall wall thermal mass and fire resistance. In the climatic conditions of cities such as Dubai, UAE, incorporating thermal mass can help regulate indoor temperatures, reduce reliance on mechanical cooling systems, and enhance overall energy efficiency. The addition of dry sand into the cavity of a 300-mm 3DCP wall significantly enhances thermal performance by increasing heat-transfer resistance by 300%, extending the time lag by 9 h, and lowering the decrement factor. These improvements contribute to greater indoor climate stability and energy efficiency.