Study On Road Performance Of The Graded Broken Stone In Frozen Soil Zone

The graded broken stone used in frozen soil zone should have well strength, frost resistance and penetrating quality. Based on the previous studies, effect of the D_max, the n value, the content of coarse aggregate and the void ratio on the strength character and the other performances of the graded broken stone were analyzed by the CBR test, freezing and thawing cycle test, permeability test and conductivity test. The design method and the construction were completed for application of the graded broken stone in frozen soil zone.According to the result of the CBR test, it can be found that the n value should be controlled at nearby 0.5, the D_max should better bigger than 31.5mm, and the content of coarse aggregate should between 60% and 65%. It also could be found that the CBR values, in certain D_max or in certain n value, are close with the void ratio between 14% and 20%. Based on the permeability test, the osmotic coefficient is increase linearly with the increase of the void ratio, as the void ratio is under 14%; however, the osmotic coefficient increase nonlinearity and quickly with the increase of the void ratio, when the void ratio is more than 14%. Base on the freezing and thawing cycle test of the other pavement materials, we analysis the effect of the water condition, the freezing temperature and it’s duration to the freezing and thawing cycle of the graded broken stone, propose the test method about frost resistance of the graded broken stone, and analysis the influence of the gradation and the number of freezing and thawing cycle to the frost resistance, and provide the frost resistance performance index base on the CBR and provide the value of the modulus of resilience. At last, we use the research result for the graded broken stone to alter and complete the design and construction of the graded broken stone in frozen soil zone.