The Design Technology Of Normal Temperature Asphalt Mixture Of Low-grade Road

According to the current standard of hot asphalt mixture(HMA),the performance indexes,which are the security,viscosity,adhesion and evaporation residue,are chose here for the asphalt used in the normal temperature asphalt mixture(NTAM).The evaluation indexes,which are material strength,water stability,high temperature stability,low temperature crack resistance and storage stability,are used for NTAM according to the current standard of the HMA and the cold asphalt mixture(CAM),and also a series of tests are designed for the indexes testing.In addition,according to the grading theory and gradation type,the suitable gradation for the NTAM is proposed.And the strength principle of the NTAM is analyzed through the Moore-Coulomb theory by three stages,and also the internal and external influencing factors of strength formation are analyzed according to the test results.First,based on a lot of indoor tests,the specifications,test methods and technical standards of the NTAM are recommended according to its original characteristics.The mixing method of HTAM should be at room temperature while asphalt mixing temperature should be at about 120?,and the mineral aggregates are not need to be heated.The specimens could be formed by Marshall Compaction molding method at the normal temperature.The AC 13 is recommended for the NATM,which is the suspended and continuous gradation type;the S type gradation asphalt mixture performance is optimal for the NATM.According the tests results,there are some affections for the strength forming of the NATM,for the internal affections are gradation type and dosage of asphalt,and the external affections are molding method,compaction work,maintenance cycle and maintenance methods.The resistance to deformation of the NATM is bad,and also for its water stability and low temperature cracking resistance,the performances of the NATM are sensitive to the temperature of mineral aggregates.The normal temperature asphalt mixture has good storage stability,but its comprehensive performance is not so good,so the NATM is only suggested to be used for low-grade road currently,if for the paving material of the highway,the performance should be improved according to the further researches.