Plus Gravel Buffer Layer To Reduce Road Reflective Cracking

With the rapid development of our economy, the high grade pavement mileage has being increasing. The asphlt pavement has been widely used in road construction because of the good leveling, a car being steady comfort and low noise. The semi-rigid base course has also been widely used as the pavement base and subbase in the high grade pavement construction because of the more powerful strength ,better stability and high rigity. Nowdays,the semi-rigid base course has become the main form in the construction of the backbone lines of the National highways.Even some low grade pavements also use the semi-rigid base material as the base. However,the semi-rigid base can have easily rupture by much dryness and low temperature. So through reduplicate vehicle load ,these interior fractures will extend to exterior asphalt to be the Reflective Cracking. The result is that the whole usage quality has been broken and more seriously the rain water can filter to the subgrade though the crack. Therefor, weakened the roadbed stability has been weakened, and cause the road has been broken earlier.Here I use the FEM calculation software to calculate pavement structure with full grade gravelly interlayer by changing the coefficient of thermal shrinkage and the modulus of the material.Though that we can analyze stress among bottom of surface asphalt layer and top of semi-rigid base. Under every kind of disadvantageous temperature field discuss the thermal stress distribution in the structure.At the same time we can observe how the graded gravel can reduce the reflective cracking .Simultaneity,combining with finite element method ,fracture mechanics has been an important way to solve crack problem in road field at present.For reflective crack under thermal load ,new conclusion can be gained if we take stress singularity at crack tip into account.It can be proved that the conclusion we get is close to the fact of road abruption.Therefor , it is very important to study the growing law of asphalt pavement using facture mechanics method. The...