The main function of asphalt overlay on old cement concrete pavement is to improve the service function of the pavement, But it does not contribute much to the load-bearing effect. The rigid concrete pavement under the overlay still plays a key load-bearing role.
The asphalt overlay on the old asphalt concrete pavement is different. And the asphalt overlay will bear the load together with the old asphalt concrete pavement. Therefore, asphalt overlay on asphalt concrete pavement will not only produce reflective cracks. But it also fatigue cracks due to the long-term effect of load.
In this paper, we analyze the loading of the asphalt overlay on the old asphalt concrete pavement. Because the flexible overlay under the asphalt overlay is the same nature as the asphalt overlay, when subjected to load, the road surface will deflect.
The asphalt overlay directly in contact with the wheel will be subjected to pressure. In the area outside the wheel load edge, the surface layer is pulled. Due to the different mechanical properties of the two stress areas, and close to each other, the sudden change of force at the junction of the two stress areas is prone to damage. Fatigue cracking occurs under long-term load.
Fiberglass Geogrids in asphalt overlays can disperse the above-mentioned compressive and tensile stresses. A buffer zone is formed between the two stressed areas. Here the stress changes gradually rather than suddenly. This reduces the damage of stress mutation to asphalt overlay. At the same time, the low elongation of glass fiber geogrid reduces the deflection of the pavement and ensures that the pavement will not undergo transition deformation.