Study On Applicability Of Flexible Pavements With Asphalt Treated Base In Frigid Region

With the rapid increase of traffic, asphalt pavements on semi-rigid base have become the main form of pavement structure since 1980s.The semi-rigid base material has many advantages, such as high intensity and strong slab entirety. However, researches and engineering practices have showed that there still exists many limits in semi-rigid base including its design and construction. Based on a large number of domestic and foreign documents concerning this subject, the paper analyzes the flexible pavements with asphalt treated base applied in frigid region, particularly in Inner Mongolia region. Some point have been drown out as follow.According to the performance required to the base course of asphalt pavement, three typical grades of asphalt treated base mixture were chosen, based on the grade limits. Fractal theory was applied to analyze the relation between the grade trend and the Fractal-dimension. Study shows the Fractal-dimension is linearly correlated with the aggregate passing proportion of the mixture 2.36mm and the voids mineral aggregate.Single-axles creep test is performed to evaluate high-temperature stability of asphalt treated base mixture. In the light of evaluating index, the effect of grade tendency on anti-permanent deformation ability is studied. By using Bending test, Bending Creep Test and low-temperature splitting test, the low-temperature crack resistance is tested. Simultaneously, Immersion Marshall Test and freeze-thaw split test is carried out to evaluate water stability. Study shows the mixture of upper grade limit is best in high-temperature stability and low-temperature crack resistance. The middle grade limit mixture has excellent water stability. Anti-deformation and low-temperature crack resistance is well related to Fractal-dimension.Considering interface shape, Pressure distribution, loading period and the contact condition between tires and road surface, the finite element method was applied to analyze the mechanics response of asphalt treated base pavement under the semi-sine wave loads. Asphalt treated base pavement can improve the force states of in the layer semi-rigid base material.With of the typical climate condition in Hulunbeier region of Inner Mongolia, the papers establish the temperature field by using the method of numerical analysis in order to study thermal stress. It is concluded that the asphalt treated base pavement can improve the temperature condition in the layer of semi-rigid base material and lower the thermal stress in the bottom of subbase.