A Hierarchical Strengthening Path for Chemical Foaming: The Transformation toward Sustainable High-Performance Foamed Material Derived from Solid Waste

Abstract

The pores of conventional foam composites easily crack and collapse under internal stress. Fabricating foamed materials (FMs) with high specific strength and excellent pore structure at ambient conditions remains a significant challenge. This study achieved hierarchical reinforcement of waste-based FMs' matrix and pores through systematic control of the "foaming−setting−curing" process. The results demonstrate that adjusting the plastic viscosity and setting time of fresh pastes can improve the pore size distribution and optimize pore microstructures. Concerning modification at the gas−liquid interface, organic additives and hydration products could mutually adsorb and bond at the pore interfaces, thickening pore walls and completing embedded structures. Moreover, the effective variable-pressure foaming process not only stabilizes chemical foaming but also enhances specific strength by accelerating hydration and improving pore wall integrity. Concerning aeration methods, the introduction of copper tailings catalyzed the decomposition of H 2 O 2 at room temperature. Additionally, the coupled effects of multidimensional stable foaming techniques suitable for H 2 O 2 foaming and the underlying mechanism are elucidated. Overall, this research offers a systematic, low-energy strategy for enhancing performance and reinforcing pores in waste-based FMs.