| The Lhasa road transport market has developed vigorously since the Sixth Central Tibet Work Symposium.However,the asphalt pavement in Lhasa area has many difficult-to-resolve diseases,such as cracks,loose asphalt and potholes,etc.;this greatly affects the service life of the asphalt pavement.Secondly,there is a shortage of limestone in the Lhasa area.The pebbles in the river are used as the aggregate of the asphalt mixture;however,whether it is limestone or pebbles,the stones themselves are acidic stones,and the lack of edges and corners of the pebbles are unconventional pavement stones.The asphalt mixture of these stones is used for roads.Using performance research,and comparing with conventional stone limestone in Kunming area,the following aspects of the problems of granite asphalt mixture and gravel asphalt mixture in Lhasa area are studied:(1)Analyze the physical properties of the stone itself(including density,abrasion value,crushing value,adhesion and broken surface of pebbles)and Marshall experiment to test whether the physical properties of the stone and Marshall-related technical indicators meet Specification index of pavement materials;(2)Analyze the fatigue performance of the asphalt mixture using the Overlay tester test,and evaluate the fatigue performance of the asphalt mixture by linear regression fitting between the maximum load of a single lap and the number of load cycles;(3)Calculate the crack growth length and the stress intensity factor of the crack tip through the regression relationship between the maximum load of a single circle and the number of load cycles;use the regression relationship between the crack growth rate and the stress intensity factor(SIF)to solve the Paris fracture constants A and n;use the stress The regression relationship between the strength factor(SIF)and the number of load cycles and the regression relationship between the stress intensity factor(SIF)and the crack propagation length can predict the fracture life of the asphalt pavement. |
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