The development of the construction industry, coupled with an increase in renovation and demolition activities, has led to the generation of substantial amounts of construction waste [1,2]. Statistics indicate that China has a stockpile of over 40 billion tons of construction waste, which includes materials such as concrete, brick, and asphalt, with an annual production exceeding 2 billion tons [3,4]. This significant volume positions China as the country with the highest construction waste production globally. Over time, harmful substances contained in construction waste can leach into the soil, initiating a series of chemical and biological reactions that disrupt the original structure of the soil and contribute to soil pollution [5]. Additionally, the long-term accumulation of construction waste often leads to the formation of strongly alkaline water seepage, which is also contaminated with a significant number of metal ions, hydrogen sulfide, and other organic compounds [6]. This wastewater is subsequently discharged into rivers, lakes, oceans, and soils, resulting in the pollution of both surface water and groundwater. It is evident that the detrimental effects of construction waste pose a serious threat to the environment upon which humanity relies and adversely impact the ecological system [7,8,9]. Therefore, the reuse of construction waste resources is not only a crucial factor in promoting the high-quality development of the social economy [10], but it also holds significant importance for the protection of the natural environment.

Current studies indicate that construction waste can be utilized as recycled coarse aggregate (RCA) in the production of recycled concrete after undergoing processes such as classification, crushing, and screening [11]. In addition, the use of recycled concrete can decrease landfill waste by approximately 65%, and its production process can reduce carbon emissions by around 30% compared to traditional concrete. Despite these significant environmental advantages, recycled concrete still encounters several technical and performance challenges in practical applications, including high impurity content, elevated water absorption, and reduced robustness [12,13]. These issues represent critical barriers to the widespread adoption and application of recycled concrete. On the other hand, many cities in China are facing the challenge of excessive rainfall during the rainy season, which poses difficulties for traditional pavement concrete materials to achieve adequate water permeability [14,15]. This issue significantly impacts daily life and traffic. Consequently, numerous researchers have increasingly focused on the use of RCA to manufacture concrete with enhanced water permeability [16,17,18], specifically Recycled Pervious Concrete (RPC). The development and application of RPC not only expand the potential uses of RCA and yield substantial environmental benefits but also provide effective water permeability solutions to address urban waterlogging.

In the current study of RPC, the replacement rate of RCA for natural coarse aggregate typically exceeds 30%. The increased use of RCA has led to a significant reduction in the mechanical properties of RPC [19,20]. Vieria et al. [21] found that the mechanical properties of RPC with a 100% RCA substitution rate decreased by 62.5% compared to samples without RCA. Similarly, in the study conducted by El-Hassan et al. [22], this decline was even more pronounced, reaching 87%. However, it is important to note that, in contrast to mechanical properties, pervious concrete often prioritizes its superior permeability. Aliabdo et al. [23] studied the effect of RCA substitution rates on the permeability of RPC. The results indicated that the permeability of RPC was 40.9%, 36.8%, and 37.2% when the RCA substitution rates were 0%, 50%, and 100%, respectively. In contrast, Brasileiro et al. [24] argue that the density of RCA is lower than that of natural aggregate, leading to a reduced density of recycled pervious concrete compared to conventional pervious concrete. Consequently, the absorption rate, porosity, and permeability of the recycled pervious concrete are increased. Additionally, Mehrabi et al. [25] conducted a comprehensive study on the permeability of RPC and also concluded that the incorporation of RCA enhances the permeability of RPC. In the aforementioned studies, the impact of RCA on the permeability of RPC has not yielded a definitive consensus. However, it can be concluded that RCA does not reduce the permeability of RPC below the thresholds established by relevant specifications. Consequently, further research is required to optimize its overall performance, particularly in balancing the relationship between mechanical properties and permeability.

In addition to the intrinsic properties such as water absorption and robustness of RCA, aggregate gradation is also a key factor influencing the performance of RPC. Dai et al. [26] suggested that pervious concrete produced with graded aggregates demonstrates a significant strength advantage over that prepared with single-size aggregates. This phenomenon can be primarily attributed to the higher specific surface area of graded aggregates, which facilitates better coverage by the cement paste, thereby enhancing the bonding strength between the paste and the aggregate. R. V. et al. [27] compared the influence of aggregate gradation bandwidth on the mechanical properties and water permeability of RPC. They found that as the aggregate bandwidth decreases, the strength and density of RPC also decrease, while porosity and permeability increase. Chen et al. [28] utilized aggregates of sizes 4.75–9.5 and 9.5–19.0 mm to prepare pervious concrete. The results indicate that an increase in the proportion of aggregates with smaller particle sizes leads to a decrease in porosity; however, permeability initially increases before subsequently decreasing. Anburuvel et al. [29] believed that an increase in the size of large particles can enhance porosity and improve permeability. While previous research has documented the influence of aggregate size in RPC on both mechanical properties and permeability, the precise relationship between these two properties remains unclear. This ambiguity arises from the inherent contradiction between mechanical properties and permeability (enhancements in mechanical properties typically lead to increased compactness, which in turn reduces permeability [30,31]). Therefore, establishing a balanced relationship between mechanical properties and permeability is a critical issue that warrants further investigation.