overlay structure
2.Two different reinforcing methodologies are applied:modification of the overlay characteristics by adding chopped glass fibers to the hot mixture asphalt (HMA) and reinforcing asphalt overlay with glass grids.Theory of fracture mechanics (FM) is employed to determine crack growth rates for the suggested anti-cracking overlay systems.Asphalt mixture designing tests,three point bending tests and fatigue crack propagation tests were carried out.The critical stress intensity factors KIC are determined for plain and reinforced asphalt concrete.Depending on the fatigue crack propagation,the crack growth rate is determined for each type of anti-cracking system and the cracking process is also analyzed.One of the significant points in this study is the attempt to give better understanding of the crack propagation for multilayer asphaltic overlay or what are suggested herein to be called composite structure anti-cracking overlay system.The results indicate that the reinforcing materials improve anti-cracking characteristics of the asphalt concrete.Composite structure anti-cracking overlay gives a good solution for the reflective cracking phenomenon over old cracked pavements.
3.On the basis of on the analysis of current spherical spatial data structure,the clew of the spherical spatial basal subdivision mode which uses Snyder equal area projection on the truncated icosahedron DGG is discussed,and then global multi-resolution overlay is obtained by subdividing hierarchically on the initial projection plane according to the hexagonal grid.
