Study On Durable Property Of Asphalt Pavement Semi-rigid Base

Semi-rigid base asphalt pavement is presently the main structure in our country, how to prevent pavement cracking early is always regarded as the very important study by the international pavement engineers. Whereas the cause of the pavement cracking: pavement destruction mainly caused by the base destruction, which is as the bearing layer. Study on elements such as: load, pavement structure and materials which effect pavement use property, plenty acknowledgement pavement structure' long-time use property by monitoring, how to advance durable property of base in order that advance pavement' life, all of these are very important, practical and significant studying.This theory aims at advancing the durable property of base, bring forwards base material' drying shrinkage cracking-resistant coefficient, base structure' tempeture stress ratio and fatigue life ratio as durable indexes. In fact, pavement base is effected by both of these influences during construction and use, it further bring forwards durable property index, which entirely considers the three durable exponent and controlled by weight coefficient.In the gradation aspect of base mixture, this theory bring forwards interlocking gradation design ways, from the experimental study on materials and physical mechanical properties of durable base to consider about modifying the base mixture, the test result shows that rational conjugation of base material could advance strength value, rigidity value and bending-resistant ablity, minimize drying shrinkage; if rubbler power diamatered 20～30 mu could be mixed into base, and asphalt emulsion be thinked as agglutinant, the strength and rigidity value of the base will be improved, as well as the bending-resistant, the early drying shrinkage strain of the material.Use finite element analysis software-ANSYS to analyze pavement and base' stress condition when the base' thickness and modulus changing, it mainly simulates when loads as travelling load, temperture distributing and coupling of the two loads acts, the structure layer' stress, after that, it analyzes the stress result in order that discuss the resonable thickness and modulus of base.Based on the materials and physicial mechanicial analysis and ANSYS stress analysis of semi-rigid base, this theory concludes fatigue life numerical calculation ways of base from the point of rupture mechanic, calculates several bases' fatigue life in different pavement structure combined finite element analysis; at the same time, bases on the the three durable indexes and durable property index which put forwarded by this paper, conbined materials and physical mechanical analysis and ANSYS stress analysis value, it calculates durable property exponents of the different pavement structure, and discusses the durable property.To verify the result of the test, the experimental project is modified maintaining design and constructed in national highway G321 in Zhaoqing of Guangdong province on base of the laboratory test, the notice during constructing modified base, three to five long-time tracking monitoring of base by embedding different strain gauge in the experimental line has been desided.