Gradation design and road performance of strongly embedded ATB-30 asphalt stabilized gravel
This work focused on the study of the feasibility of crushed gravels in the northwest arid desert area in the preparation of ATB-30 mixes and the corresponding road performance.Firstly,the coarse aggregate gradation and fine aggregate gradation were designed using the grade-by-step filling method and the variable I method during which the minimum void ratio and optimum mechanical properties were taken as the judgment criteria,respectively.Secondly,the effect of each 0-4.75 mm aggregate and 4.75-9.5 mm aggregate mass ratio(2∶1,3∶1 and 4∶1)on the mechanical strength of ATB-30 asphalt stabilized gravel at different mortar dosages(m砂,1.03m砂 and 1.06m砂)was studied,and the strong embedded skeleton dense gradation of ATB-30 asphalt sta-bilized gravel was proposed.Finally,high-temperature rutting test,low-temperature bending test,freeze-thaw splitting test and water immersion Marshall test were conducted,and the results from which were compared with the median value of the standard grading to evaluate the improvement effect of its road performance.The results show that the best fine aggregate gradation is achieved at I=0.75,and the best coarse aggregate gradation is achieved at a mass ratio of 7∶3 between 19-37.5 mm and 9.5-19 mm aggregate.In addition,the best mechanical index is achieved at a mass ratio of 3∶1 between 0-4.75 mm and 4.75-9.5 mm aggre-gate at a theoretical mortar dosage of 1.03m砂.The ratio of coarse to fine aggregate is 7∶3 at this time,which is higher than the median value.Compared with the median value of the normative grading,improvements of about 21%,9%and 3%were observed respectively for the high-temperature rutting performance,low-temperature cracking resistance and water stability performance of the proposed strong embedded skeleton compacted grading ATB-30 asphalt stabilized gravel.
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