To conduct a more in-depth study on carbon emissions and influencing factors during the materialization stage of prefabricated buildings, this paper focused on a residential prefabricated building in Beijing. The LCA method, combined with BIM technology, was utilized to establish a process-based “LCA-BIM” carbon emission statistical platform and to propose a carbon emission calculation method. The carbon emissions during the materialization stage were calculated. The results revealed that the production of building materials contributed the highest proportion of carbon emissions, accounting for 85.73% of the total emissions during the materialization stage. Specifically, reinforcing steel and concrete dominated the overall carbon emissions from building materials, accounting for 97.44% of the total. Through a quantitative analysis in the process of carbon emissions calculation, the main factors influencing the carbon emissions during the production stage of building materials were identified. This study adopts a combined approach of empirical analysis and a literature review, establishing six basic hypotheses for four aspects: material selection, energy consumption, material storage, and carbon emissions in the production stage of building materials. A structural equation model was used to theoretically validate the influencing factors in the production stage of prefabricated building materials. SPSS27.0 and AMOS28 software were employed for data analysis. From the perspective of the overall impact, material selection had the strongest overall impact on the production stage of building materials, followed by energy consumption, while material storage had the smallest overall impact. From the perspective of direct impacts, energy consumption had the strongest direct impact on the carbon emissions in the production stage of the building materials. The findings of this study can provide a theoretical reference for national institutions and businesses for carbon emission evaluation and decision-making.

Recycled aggregate concrete (RAC), composed of aggregates sourced from construction solid waste, has garnered significant attention owing to its notable environmental friendliness. In this study, waterborne epoxy resin (WER) and steel fibers (SFs) were introduced into the RAC to enhance its performance. Orthogonal tests were meticulously designed, with the substitution rate of recycled aggregate (RA), SF dosage and WER dosage as variable factors, to comprehensively analyze the splitting tensile strength and impact resistance of concrete. The impact resistance of concrete was investigated via the drop weight test method. Furthermore, scanning electron microscopy (SEM) was employed to scrutinize the microstructure of concrete, investigating the modification mechanism of WER. The results indicated that the addition of SFs exerted the most pronounced influence on the properties of RAC. As the addition of SFs increased from 0 to 1.0%, there were significant enhancements in the splitting tensile strength and impact energy of the specimens. WER exhibited notable improvements, primarily on the splitting tensile strength, while demonstrating an adverse effect on the impact resistance. Utilizing the Weibull distribution theory, the results of the impact tests were fitted and analyzed to predict the impact life of different mixtures. The predicted results showed high correlations with the measured values.

Geopolymeric recycled aggregate concrete (GRAC) emerges as an alternative to ordinary concrete, presenting promising prospects in practical engineering due to its exceptional performance and eco-friendly attributes. Nevertheless, GRAC exhibits deficiencies in toughness and brittleness. To address this concern, this study investigates the potential of waterborne epoxy resin (WER) in enhancing the properties of GRAC. Experiments were conducted using WER and recycled aggregate (RA) content as variables, focusing on the setting time, fundamental mechanical strengths, stress–strain response and microstructure of GRAC. The findings indicate that the increase in the RA content results in an overall deterioration in the mechanical performances of GRAC. Nevertheless, the addition of WER effectively mitigates the adverse effect of RA substitution, enhancing the splitting tensile and flexural strengths of GRAC. The addition of WER leads to a growth in compressive toughness, and the post-peak stress–strain curve of GRAC exhibits a flatter trend, indicating enhanced ductility. WER interacts with C-A-S-H, forming a compact organic–inorganic interpenetrating network structure, which strengthens the GRAC matrix. Moreover, the incorporating 4% WER content leads to a reduction of 31.2% in the total porosity of GRAC, in contrast to GRAC without WER. Drawing from experimental results and prior researches, a refined stress–strain model is presented to provide comprehensive depiction of the compressive stress–strain curve of GRAC considering differing dosages of RA and WER. Finally, Life Cycle Assessment (LCA) of GRAC results demonstrate its superior environmental performance as a low-carbon material relative to ordinary concrete.

Recycled aggregate concrete (RAC) is commonly limited by high porosity, weak interfacial transition zones, and poor impermeability. In this study, waterborne epoxy resin (WER) and steel fibers (SFs) were jointly used to improve the performance of RAC. Concrete with a target compressive strength class of 40 MPa and a 50% recycled coarse aggregate replacement ratio was selected as the main system. Mixtures with different WER dosages and SF contents were prepared. Mechanical properties, porosity, impermeability, microstructure, and direct material cost per cubic meter were investigated. The results showed that WER and SF produced a clear synergistic effect. WER mainly improved matrix compactness and interfacial bonding, while SF mainly restrained crack initiation and propagation. The optimum performance was obtained at 4 wt% WER and 1.0 vol% SF. Compared with the unmodified RAC control, the optimized mixture showed higher strength, lower porosity, and better impermeability. Scanning electron microscopy observations further confirmed the formation of a denser internal structure and improved interface quality. Although the direct material cost increased after modification, the optimized RAC showed better overall engineering applicability, particularly for water-resistant and durability-critical structures.