Study On Segregation Mechanics And Quality Control Technologies Of Superpave HMA During The Course Of Mechanical Construction

Superpave HMA is a new type mix, it has developed along with the incessant development of freeway disease increasingly serious, such as high temperature rut, low temperature crack and water damage. And it has great shearing strength, highly resistant to rutting and distortion, therefore, this type mix emerged as the time require and has been used for its advantage in some construction of highways of overseas and home. As Superpave is unique to series grade and coarse-graded mixtures, belongs to the category of mix rather difficultly construct and compact. So a number of segregation problems do existing easily is the inherent defect of the type mix during the course of construction, which seriously affects the mixing quality and performance. At present operators of freeway in overseas and home have given enough regard to segregation of hot mix asphalt, however, for Superpave mix especially, there is no systemic research on the problem of construction technology and quality control. For solving this problem, the causation and eliminating methods of the construction technology were studied systemically in the placement of Superpave mixture.This reporting began with the design ideas of Superpave mixture, analyzed one-sidedness of traditional design concept, many think it is probable to pave ideal road only if design the ideal mixture. According to the study on reasons and mechanisms of Superpave mixture segregation in mechanized construction process, a new mixing design concept was put forward. It is considered that the placement uniform of HMA, layer quality, the parameter adjusting of equipment and construction technology is all correlated nearly, not just relied on the mix design.Staring from structure of the production equipment and the physical character of aggregate, constructors introduced infrared photography and nuclear gauge and so on advanced apparatus in the job locations. Several segregation reasons of mixture in production and construction were analyzed. The parameter calibration and adjusting of mixer and pave were revealed. According to the material mixture, different elimination principle and methods to minimize segregation were discussed and corresponding mechanisms and effects were expatiated severally. The results indicated that it is necessary to use auxiliary means or improve the existing structure...