Optimization-Strategy for Incorporating Recycled Brick-Powder in 3D Printed Concrete by Balancing Low-Carbon Footprint and Enhanced Performance (2024-08)¶

The high cement content in 3D-printed concrete (3DPC) presents challenges for achieving a low carbon footprint. Substituting a portion of cement with recycled brick powder (RBP) is a crucial strategy for reducing carbon emissions while enhancing fresh and hardened properties of 3DPC. Balancing RBP preparation energy consumption with its impact on 3DPC performance is crucial for efficient, low-carbon RBP utilization. Two types of RBP were obtained through crushing, sieving (RBP-S, more low-carbon), and grinding (RBP-G). RBP-G with finer particles can enhance the green strength evolution by expediting the initiation of the hydration acceleration period and increase heat flow of this period. 3DPC containing 40 % RBP-G exhibits the lowest porosity, with a rise in gel pores and a drop in macro-pores attributed to the filling effect and pozzolanic activity. RBP-S exhibits a better internal curing effect. Replacing 40 % of cement with RBP-S or RBP-G can reduce drying shrinkage of 3DPC by 30 %. RBP-G excels in enhancing the mechanical properties of 3DPC, whereas RBP-S demonstrates superior performance in terms of environmental and economic benefits. This study presents novel viewpoints on leveraging RBP for low-carbon applications and optimizing the performance of 3DPC.