Economic Evaluation On Rational Asphalt Pavement In High Altitude And Cold Permafrost Area

The natural environment characteristics of low temperature,great temperature difference,strong radiation and widely spread various permafrost types,as well as large heavy traffic high altitude and cold area,which made road construction in huge difficult.These challanges are expressed in a performance,including quickly decay of subgrade pavement performance,short and difficult construction period,various and heavy density of road damages,low driving safety and comfort.This paper analyzes the limitations of the existing structure through the investigation on the hazards of subgrade and pavement,and recommend the form of pavement structure fitted for high-altitude area.Study on pavement behavior was carried out with the calculation method of numerical simulation.According to the principle of "reasonable before economy",the whole life cycle cost of reasonable highway pavement structure in test section was calculated.Finally,a pavement structure with well technical and economical would be recommended.The qinghai-tibet and the qingkang highway has been built in the area of high altitude and cold.Through the census and main investigation on typical sections of this three routes,and combined with natural environment conditions,characteristics of permafrost and the Qinghai-Tibet highway road conditions,analysis the characteristics and causes of disease in the roadbed and pavement.At last reasonable pavement structure suitable for permafrost area was put forward.The first-stage project of Gonghe-Yushu highway form K629 + 800-K634 + 200 was taken as test section for establishing the semi-rigid base asphalt pavement,composite asphalt pavement and flexible base asphalt pavement structure and subgrade numerical model in permafrost regions.The boundary conditions,initial conditions and material parameters and constitutive models are determined.The temperature in subgrade and pavement,deformation and bottom layer tensile stress in the structure of pavement was calculated.The rationality of the test section of pavement structure was verified.Under the premise of road performance have meet the requirements,the cost of reasonable pavement structure in construction with the help of cost software.Based on field research,using the grey-markov prediction model to evaluate and predict the test road pavement condition index(PCI)of Gonghe-Yushu highway.Last,the maintenance time and scheme of test road is determined.Based on the whole life cycle theory,through the calculate the whole life cycle cost on four test road pavement structure of the first phase project of Gonghe-Yushu highway,the graded broken stone base asphalt pavement structure was determined as the most economic and reasonable structure.