Project 9.1 (2019)
Background
Rutting, fatigue crack, reflection crack, temperature crack, and potholes are the major failure mechanisms in asphalt pavement. The common practice is to lay a cover layer on cracked pavement (for cracks), or dig and backfill followed by resealing (for rutting and pothole failures). Failure could repeat on the same location a few years after rehabilitation. The repeated failure could attribute to stress concentration and variation of base material properties. Refiling and resealing do not change the load transfer mechanism into the base and subgrade, and in some cases may make the situation worse, if more variation is caused during the repairing process.
Research has been done to include a layer of geosynthetics beneath overlaying layer to increase the life of the overlaying layer [1, 2]. Most of the research is on the effectiveness of geosynthetics on preventing / delaying the development of cracks in asphalt layers. No design method has been proposed for such structures. Geogrid has been used in practice in recent years below the top asphalt layer to increase the life of the surface structure. With the increasing usage of geogrid reinforced asphalt pavement, it has become urgent to propose a design method to consider the effect of geogrid in the system.
The objective of this research is to study the reinforcing mechanism of a new type of geosynthetics, which includes a layer of fiber-glass geogrid on top of a thin layer of geofabrics, place below the asphalt layer, and its effect in reducing cracks in the asphalt layer considering the property variation of underneath layers, and the variation of asphalt layer. The variations would include the stiffness and strength parameters of underneath soil layer, the thickness and temperature of the asphalt layer, loading level and loading frequency, etc.
Project Objectives
1. Study the reinforcing mechanism of geogrid reinforcement in the sealing layer of pavement
2. Behaviour of reinforced sealing layer resting on different base materials underrepeated loading
3. Optimization design of reinforced sealing layer considering the variation of base and sub-base materials
- Dr Jianfeng Xue (LCI - The University of NSW)
- Professor Jayantha Kodikara (Monash University)
