## 1 Introduction  
With rapid economic development, global urbanization has reached an unprecedented level. High urbanization generates excessive resource consumption and increased carbon emissions, which results in great changes in the global climate [1]. Cities are increasingly feeling the effects of extreme weather and many urban problems are caused by climate change, such as flooding and urban heat island phenomena [2]. It is extremely urgent to seek solutions for the mitigation of climate change impact and urban water management [3]. Pervious concrete, also called porous concrete, has been used since the 1970s in the United States and Japan. It is a kind of porous lightweight concrete made of aggregate, cement, and water. It has a honeycomb structure with uniformly distributed pores formed by coarse aggregate and a thin layer of cement paste [4; 5]. With little or no fine aggregate, pervious concrete (PC) has the characteristics of high permeability, high noise absorption, and high heat dissipation [6; 7; 8]. Compared to traditional impervious concrete pavement, PC pavement is a functionally and environmentally friendly material [9]. It allows rainwater to permeate into the ground and replenish groundwater, which effectively alleviates the rapid decline of groundwater. In addition, PC pavement can solve other urban environmental problems [10; 11; 12]. With the development of Chinese sponge city construction, PC will be widely applied in road structure [13]. Therefore, PC is of great significance for mitigating climate change, solving urban problems, and promoting the development of human society [14; 15; 16]. The main properties of PC are strength, permeability, and durability. A porous structure is the key feature of PC, and porosity is the most important factor influencing mechanical strength, permeability, and durability. In general, the porosity of PC mixtures is 15-30% and the corresponding permeability coefficient lies in the range of 1-15 mm/s [17; 18]. Higher porosity produces higher permeability, but is disadvantageous to mechanical strength and durability. Due to the absence of fine aggregate and the existence of high porosity, the strength of PC is lower than that of traditional impervious concrete. The compressive strength of PC is 5-30 MPa and tensile strength is 1.5-4.0 MPa [19; 20]. In addition, the freeze-thaw durability of PC is a very important property, especially for PC used in seasonally frozen regions. However, the freeze-thaw durability of PC is significantly lower than that of conventional concrete. Based on the characteristics of PC, it is widely used in low-volume areas such as parks, sidewalks, squares, airports, and residential roads. A large number of laboratory studies have been conducted focusing on properties of PC. [PERSON] et al. [21] used the orthogonal test method to study the influences of aggregate type, cementitious material dosage, and molding pressure on the permeability coefficient of PC. The experimental results showed that the aggregate type had no effect on the permeability coefficient, and the permeability coefficient decreased with an increased amount of cementitious material and forming pressure. [PERSON] et al. [22] proposed an improved design method for PC based on the aggregate surface area and cement mortar layer thickness. The PC designed with this method had a compressive strength of 28.6 MPa and a permeability coefficient of 1 mm/s. The compressive strength was higher than what was reported in other studies. [PERSON] et al. [23] studied the permeability of PC pavement in parking lots. It was concluded that age was the most important factor affecting permeability. [PERSON] and [PERSON] [24] produced 18 groups of PC specimens with different aggregate sizes and the permeability coefficients were measured with a falling head permeability test.