What's the purpose of laying a layer of sand under the permeable paving bricks? Let's analyze:

1. The underlayer sand should be semi-dry. The method of moisture control is: mix the material with the labor-saving compound into a mass, loosen it, and it will naturally disperse to meet the standard. Underlayer sand with suitable dry and wet conditions is beneficial for leveling the road surface, reducing dust, and improving the compactness of the underlayer.

During the water washing process, the sand mat should be coarse sand. Due to resource limitations, no specific physical specifications for the sand mat are provided here.

Layer sand has excellent permeability to ensure that water from eco-ceramic permeable bricks can seep into the permeable subbase in a timely and effective manner. Therefore, it should be emphasized that cement or lime blended binder should not be used as sand cushion layer.