Abstract: Carbon nanotube is an emerging material with excellent mechanical properties and electrical properties in recent years. The addition of carbon nanotubes to epoxy resins can be made into composites with sensing effect. The bipolar method was used to determine the percolation threshold of carbon nanotube epoxy composites by changing the concentration of carbon nanotubes. The effects of temperature and humidity on the electrical conductivity of the composites were investigated. At the same time, the cyclic loading method was used to study the pulling sensitivity of the composite. It was found that the intervals of percolation threshold of carbon nanotubes epoxy resin matrix composites was ranging from 0.5wt% to 0.8wt%. In this interval, with the increase of the amount of carbon nanotubes, the electrical resistivity of the carbon nanotube epoxy composite decreased significantly. As the temperature increases and decreases, the resistivity of the composite material also shows a corresponding increase and decrease. Moisture in the environment has almost no effect on the resistivity of the composite. The pulling sensitivity of the material appears obviously when the amount of carbon nanotubes is 0.9wt% and the pulling sensitivity fades away when the amount of carbon nanotubes is 1.2wt%. It is proved that the pulling sensitivity of the material is the best when the amount of carbon nanotubes is 1.0wt%.

Key words: roadwork, carbon nanotube epoxy composites, the percolation threshold, resistivity, the pulling sensitivity