Improvement of Physical and Mechanical Property as well as Planting Property of Planting Concrete by Multi-Functional Synergy of Coal Gangue Characteristics

The environmentally friendly coal gangue planting concrete (CGPC) was prepared by leveraging the porous structure, nutrient reserves, potential reactivity, and solid waste characteristics of coal gangue. This provides an effective approach to comprehensively enhance the resource utilization of coal gangue solid waste and promotes ecological environmental governance. CGPC was prepared using activated coal gangue powder (ACGP) as a supplementary cementitious material and coal gangue as the aggregate. The influence of ACGP on the physical and mechanical property of CGPC was studied. Meanwhile, the influence of coal gangue powder as part of the guest soil on the planting property of CGPC was also studied. The results showed that low-content ACGP can fill the micropores in CGPC by micro-aggregate and pozzolanic effects, optimizing the structure of the interfacial transition zone between aggregate and paste, and significantly improves its mechanical property and frost resistance. The secondary hydration reaction of ACGP consumes a considerable amount of Ca(OH)2, significantly reducing the alkalinity of CGPC and forming a more suitable environment for plant growth. Incorporation of 20% to 40% coal gangue powder into the guest soil effectively improves the growth status of the three plant species, especially Elymus dahuricus exhibits the most significant improvement.