Structure of Permeable Concrete

As urbanization deepens, the coverage area of reinforced concrete is increasing, and urban land is gradually becoming hardened. Coupled with unreasonable designs of drainage systems in old cities, the problem of urban water accumulation has become increasingly prominent. The emergence of **permeable concrete** has gradually replaced impermeable pavements, effectively alleviating the negative impact of impermeable hardened surfaces on urban water resources. **Permeable concrete** allows rainwater to directly infiltrate into the underlying soil through porous pathways in the base layer. However, different structures yield different drainage effects. So, what are the structures of permeable concrete? 1. Internal Overflow Structure There are two types of **permeable concrete**: the first type has a permeable base layer with an internal overflow drainage structure. This base layer can temporarily store rainwater that seeps through the pavement and then further infiltrate. Its water storage structure includes a leveling layer, a gravel layer, and a permeable geotextile. The second type has a non-permeable base layer with an internal overflow drainage structure. This base layer can store rainwater that seeps into it for an extended period. A non-permeable geotextile is set between the base layer and the leveling layer, preventing rainwater from directly infiltrating underground, and instead, it is discharged outside through internal underground pipes. This base layer is suitable for areas with heavy rainfall, low soil permeability, low load-bearing capacity after water infiltration, and locations where water source pollution may occur. 2. Small Water Storage Capacity The colored **permeable concrete** pavement base is mainly composed of a leveling layer and a permeable base layer. The permeable base layer has a high void ratio but is not very thick, providing strong permeability, making it suitable for regions with low rainfall, strong permeability in the base layer, and high load-bearing capacity. It is mainly applicable to sidewalks, non-motorized vehicle lanes, squares, parking lots, pedestrian streets, courtyards, and similar areas. 3. Peripheral Overflow Structure This structure can be categorized into three situations: the peripheral overflow of **permeable concrete**, the overflow structure of impermeable pavements, and the permeable landscaping paving materials. Similarities: All three types of **permeable concrete** can drain rainwater outside during rainfall, preventing water accumulation on the surface. Differences: The impermeable pavement can withstand light loads but cannot support heavy traffic, while the other two types can meet the load-bearing requirements.