To improve the workability and mechanical properties of Recycled Micro-Powder (RP) mortar, basalt fiber (BF) was used for modification in this study. Experimental groups with different BF contents (0%, 0.1%, 0.15%, and 0.2%) were designed to investigate the effects of BF on the flowability, flexural strength, and compressive strength of RP mortar. The microscopic reinforcement mechanism was further revealed through Scanning Electron Microscopy (SEM). Additionally, an early strength prediction model for the mortar considering the synergistic effect of BF and RP was established. The results show that the incorporation of BF significantly enhanced the mechanical properties of RP mortar. At the 28-day curing age, when the RP replacement rate was 10% and BF content was 0.15%, the flexural strength increased by 9.7%, and the compressive strength increased by 17.3%. At an RP replacement rate of 30%, the compressive strength still increased by over 30%, demonstrating a good “performance compensation” effect. However, the inclusion of BF also led to a decrease in flowability, with a maximum reduction of 25.5%. SEM analysis revealed that BF improved the matrix densification and interface bonding performance through crack bridging and physical anchoring. The established early strength prediction model achieved a high goodness of fit (R² > 0.92), indicating high accuracy and engineering applicability.

Against the backdrop of China’s “Dual Carbon” strategy—the national strategic goal of achieving carbon peaking by 2030 and carbon neutrality by 2060—and the accelerated improvement of the solid waste governance system specified in the 15th Five-Year Plan, the low-carbon recycling of construction waste has become a core research topic for the sustainable development of the construction industry. To systematically reveal the evolutionary laws, research hotspots and frontier trends regarding the life-cycle carbon emissions of recycled concrete (this study defines its accounting scope clearly for the first time, covering three parts: ① direct carbon emissions generated in the stages of recycled aggregate recovery, processing, transportation and concrete mixing; ② indirect carbon emissions reduced by replacing the exploitation of natural aggregates with recycled aggregates; ③ potential carbon sequestration benefits brought by carbonation curing during the service phase of recycled concrete), the literature published from 2015 to 2025 retrieved from the CNKI and Web of Science Core Collection databases was selected as the research sample. Standardized data preprocessing was carried out: intra-database duplicate literatures were removed based on titles, authors and publication years, cross-database duplicate records were manually eliminated, and non-academic documents including news, editorial notes and conference abstracts were screened out. A total of 1340 valid publications were finally obtained to form the analysis dataset. Bibliometric tools CiteSpace and VOSviewer were adopted to quantitatively analyze the annual publication trends, national and institutional distribution, keyword co-occurrence clustering and temporal evolution characteristics in this research field. The results show that the annual publication volume concerning the life-cycle carbon emissions of recycled concrete presents a continuous upward trend, and the research development can be divided into three stages: initial exploration, rapid expansion and steady growth. China, the United States and Australia act as the core research forces in this field. Current research hotspots mainly focus on recycled aggregate modification, life-cycle assessment, carbon emission accounting, durability performance optimization and low-carbon preparation technologies, while research frontiers are gradually shifting toward multi-source data fusion, machine learning-based carbon emission prediction and low-carbon path optimization. Based on the quantitative bibliometric results, this study puts forward targeted priorities for future research: establishing a unified localized specification system for life-cycle carbon accounting, developing data-driven optimization models for the low-carbon mix proportion design of recycled concrete, and promoting the large-scale engineering demonstration and application of high-value resource utilization technologies, to facilitate the full life-cycle low-carbon transformation of construction waste recycling.