Development And Application Of Large Particle Size Aggregate Interlocking Base Material

In recent years,with the rapid development of China's economy,the growth of traffic,the increase of heavy and overloading,and the channelization of vehicles have become increasingly prominent.The semi-rigid structure of traditional asphalt pavement is prone to reflection cracks under heavy traffic,which is difficult to cure.Although the distribution of the flexible base is relatively uniform,the existing flexible base material has the problem of insufficient strength,which makes the pavement structural layer thicker and is prone to rut and other diseases.A large number of studies have shown that increasing the aggregate particle size and adjusting the gradation of the mixture to form an interlocking structure can improve the mechanical properties of the material.Therefore,in order to better solve the problem of the strength of flexible pavement materials and resist heavy traffic,this paper conducted the following research:First of all,based on the plane three-circle stacking theory,the Bailey gradation design method and the SAC gradation design method,the key control sieve of the large particle size interlocking gradation design is determined,and the large particle size interlocking mixture Calculation method of grading.At the same time,in order to ensure the formation of the interlocking gradation,the 1/2 largest particle size sieve is especially proposed as the key control sieve of the large-diameter interlocking base material gradation design.The upper and lower limits of each key sieve pass rate are determined,and the upper and lower limits of the gradation curve are formed by the fuller gradation curve using the section calculation method,and the upper and lower limits of the gradation curve are formed.In order to better control in the mix ratio design.Secondly,in order to test the road performance and mechanical properties of the large particle size interlocking asphalt mixture,it is better applied to the test road.First,the optimal asphalt dosage of the three mixtures of ATSM-25,ATSM-30,and ATSM-40 was determined by the Marshall mix design method;secondly,the common material ATB with the same diameter and flexible base was selected as the control group,and the high-temperature rutting test was passed,Low-temperature anti-cracking test,water stability test to systematically evaluate its road performance.Finally,through the dynamic modulus test to explore the mechanical properties of ATSM,the main curve of the dynamic modulus of ATSM is obtained.The results show that the high temperature,water stability and mechanical properties of the ATSM mixture can meet the specifications.Compared with the same maximum particle size ATB material,the high temperature stability is increased by 20%-40%,the low temperature crack resistance is improved by 20%-35%,the water stability is slightly better,and thedynamic modulus is increased by about 20% on average.Again,in order to test the mechanical properties of large-grained interlocking graded crushed stone.First determine the uneven coefficient and curvature coefficient of the IGSB-50,IGSB-60,and IGSB-70 gradation curves,and reduce the gradation of the large-grained interlocking graded gravel by the mixed scale method.Then through the compaction test to determine the best water content and maximum dry density of IGSB-50,IGSB-60,IGSB-70.Finally,according to the requirements of the specification,test the CBR value and rebound modulus of IGSB-50,IGSB-60,IGSB-70,and select the traditional continuous gradation and skeleton gradation crushed stone as the control group.The results show that the CBR values of IGSB-50,IGSB-60,and IGSB-70 can meet the requirements of the specification,and can be increased by 20%-35% compared to continuous grade and skeleton graded gravel;the dynamic modulus meets the specification Requirement,compared with the continuous type and skeleton type graded gravel can increase about 40% on average.Finally,based on the mechanical data obtained from the indoor test,combined with the traffic data of the test road,through the ABAQUS finite element analysis software,a mechanical analysis of the Zhengdeng Expressway structural scheme was carried out to determine the test road pavement structure.The construction technology plan and quality control measures of large-grained interlocking base material were put forward.After the paving was completed,the test section was tracked and observed,and the test data of the test section was analyzed and summarized.The results show that the large particle size interlocking base material is more resistant to heavy loads than the traditional pavement structure;the test road has a good construction effect.After one year of observation,there are no problems such as rutting and cracks.