The principle of the cooling effect of the ballast embankment is introduced in this paper,and the temperatures at different positions of the ballast embankment are compared with those of the ordinary embankment.

So, the classification of stone chips can re- fer to the division of flake platforms.

Application of slurry seal technique to sand-gravel pavement of country roads;

The maintaining methods of sand-gravel pavement;

A technique of maintenance for sand-gravel pavement in the border aress;

Combined with concrete condition of Dianjiang-Linshui expressway project,the article introduces the comparison and selection of pavement macadam materials,quality management method and control essentials,and draws concrete conclusions,in order to ensure the quality of expressway and prolong its service life.