The Pavement Perormance Research Of Asphalt Pavement's Semi-Rigidity Base

The load bearing capability of semi-rigidity pavement is dependent on the strength and thickness of semi-rigidity base and subbase. These two structure layers are the key layer of the semi-rigidity asphalt pavement , the quality of the road base affect directly the whole pavement and have very important affection on the usage quality and service lifes of the pavement.Through more than ten years of the design construction fulfillment, Hebei province has already become a few familiar roadbase structure by inorganic binder stability crushstone mixture.The Jingzhang second highway is Hebei at the earliest stage construction of high grade highway, what to adopt was the lime cement at that time cement stability crushed stones.This structure have the favorable water stability,the plank body and anti- temperature deformability.It need less cement content,and have high intensity on late stage, but the construction request to construct according to cement crushed stones, namely to complete all grinding the cement final set.From Jingshi highway ,it gradually replace by two ash(the lime and fly ash). lime-flyash graded broken stone has the better water stability, the plank body and crack resistance.especially along with the age growth ,the strength increase very quickly, and be free from the restriction of time during the period of construction. The highway of Hebei province use lime-flyash graded broken stone in the bottom layer of the roadbase, and add some cements.the upper level of roadbase adopt cement stability crushed stones.The cement stability crushed stones have higer strength and stiffness,the water stability and anti-erosion is better. Along with enhance of construction machine and construction level, currently we can attain its construction request completely.Because lime rock in Hebei province is abundant, the aggregate of the roadbase adopt usually the lime rock.But in some mountain areas and before the mountain, the natural gravel keeps quantity to compare greatly, and the gradation is good.So through experiment to verify its road use performance, it also is a kind of good roadbase material source.The selection of base material should accord economy principle,we should comprehensive consider use local materials,alternative optimum, material source ,construction technique, economy etc.We should determine roadbase structure type in different area adjust measures to local conditions.