Biofunctionalized Waste Brick Powder to Enhance Performance of Blend Cement Mortar

Abstract

Utilizing waste brick powder (BP) as an alternative binder in cementitious materials is a low‐cost option for recycling waste BP. However, the degradation of concrete properties triggered by the low activity of brick dust is still a widespread concern. Hence, this study utilizes plant‐based tannic acid (TA) to modify BP, enhancing its surface activity and achieving high‐value utilization of the BP. The research content involves studying the physicochemical changes on the surface of modified BP and analyzing its impact on the mechanical properties of mortar at macroscopic and microscopic scales. The study shows that TA mainly adheres to the BP surface through O─C═O and C─OH bonding and in situ chelates with calcium elements to form nanoscale microcrystals (as evidenced by X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) tests). These phenolic hydroxyl groups and nano‐microcrystals collectively regulate cement hydration, resulting in a dense pore structure and a homogeneous BP‐paste hydration interface (as confirmed by nanoindentation tests), optimizing the mechanical and shrinkage properties of the mortar. BP modified with 0.1% TA showed a 26.32% increase in compressive strength and a 15.64% increase in flexural strength at 28 days, with a 25.08% reduction in shrinkage after 90 days. These findings provide a possibility for the preparation of excellent performance of BP concrete and realize the efficient application of BP.