The Research On The Effect Of Doses Of Cement On The Pavement Performance Of Macadam Base

Based on semi-rigid base asphalt pavement easily bring reflection crack,however, graded macadam Flexible base falls short of intensity and resistance to deformation in some degree .This paper introduced into a new concept that is called modified graded macadam or low doses cement of graded macadam .This kind of cement treated material ,in the condition of emphasizing on the fine grade ,has a low dose of cement for binder , and effect on felting among the aggregate ,improve the mixture intensity and shear ability. Furthermore, this kind of base material can stop. reflection crack producing.At first, this paper carried through determining a series of analysis of mechanical property, including compression module,CBR,unconfined compressive strength indices etc.The second,it researched on the dry shrinkage and shear behavior of low doses cement of gradedmacadam ,because of joining the low quantity of cement in the graded macadam, its mechanical property, the shrinkage performance and the shear behavior may be able to have the change,but the change of these performance of the low doses cement of graded macadam base are advantages which are accompanied by disadvantages.It concretely manifest that its intensity can obtain enhancement in certain degree along with the cement increasing. but simultaneously,when the quantityof the the cement mixes increasing, the dry shrinkage of the material will also be able to increase,and accelerate the production of reflection crack in the base. Therefore, the purposeis to find balance point in the advantages and disadvantages to achieves to optimization for the base performance. It conclude a most suitable dose of cement of the base material.And then, by using the Finite Element software to base on the 3D nonlinearFinite Element Model of the low doses cement of graded macadam , pavement deflection and tension stress on the bottom of base can be calculated with the different thickness of the base by the Finite Element software. Then it was concluded a suitable thickness of the base by compare to the results. In addition, because of the especial base, it was used by the Duncan-chang model to calculate the results. This model can more relevantly reflect the non-liner of the material. Therefore , the results was closer to the real value.And it is researched that the low doses cement of graded macadam base is heavy load function during keeping in good health.It Obtains basic unit keeping in good health how many days after the finite element computation, may allow the construction vehicles to pass through.it carrys on the computation to the life of the low doses cement of graded macadam base when the integrity loses,and obtains the N eof the different cement to mix under the quantity of the graded macadam base asphalt pavement.In the end , according to the construction condition, summarize the construction technology of the low doses cement of graded macadam base.