废弃混凝土再生微粉的基本问题及应用

Resourcing of waste concrete and its application as recycled aggregates have made significant progress. However,research on recycled fine powder derived from waste concrete is still limited. Therefore,this paper focuses on the preparation,characterization,and modification of recycled fine powder,clarifies the mechanisms for its fundamental problems such as high component discreteness (i. e.,the number of mineral phase species)and low activity index,and proposes a novel solution,that is,the introduction of particle shaping and strong magnetic separation technologies into the preparation process of recycled fine powder,followed by carbonation modification. It is expected that the above-mentioned problems can be addressed by taking carbonated recycled fine powder with ultra-high paste content as the outlet. Furthermore,low-carbon application scenarios of recycled fine powder are discussed,including Portland-recycled fine powder cement,3D-printed recycled mortar,and fully recycled concrete. Further research and value-added use of recycled fine powder are known to be significant for the improvement in resourcing ratio of waste concrete as well as for the green and low-carbon development in building industry.