1, the construction cost is too high: the project construction cost of highway subgrade and pavement is high, mainly because the materials and equipment involved in earthwork excavation and backfilling, subgrade reinforcement and pavement laying are expensive.

2. Unstable construction quality: In the construction of highway subgrade and pavement engineering, the construction quality of some projects is poor, or the pavement is damaged or collapsed soon after delivery, which brings some inconvenience to the use and maintenance of highways.

3. Problems in expressway pavement maintenance: The expressway pavement needs to be maintained every year, but the quality and efficiency of the maintenance work need to be improved, especially in some remote areas and mountainous areas, and the maintenance work needs to be further strengthened.