Researching On Mechanical Behaviors And Fatigue Properties Of Cement Stabilized Recycled Aggregate Pavement Base

In recent years,more and more concrete waste is generated while pavement materials is getting scarcer.Therefore,it has practical meaning to study the application of recycled aggregate in pavement base course.In this paper,the basic mechanical properties and fatigue properties of pavement base tests were used to study on some road properties of base materials and then find out the influence of recycled aggregates.Based on the test results,the main conclusions are summarized as follows:(1)For the gradation,a single aggregate can not meet the requirements of continuous grading.In other properties,the performance of natural aggregate is better than that of recycled aggregate in addition to the content of needle-like particles.All materials Physical and mechanical properties of recycled aggregate can meet the specification except the water absorption rate beyond the standard value and adverse to the strength of the base.(2)Based on compaction test,the relationships of cement content,recycled aggregate content,the maximum dry density and the optimal water content was obtained.According to the 7d unconfined compression test of the mixture and the comparison with the standard,the recycled aggregate used as cement stabilized pavement base is feasible.(3)The strength and stiffness of the mixture increase with the increase of the cement content.When the cement content is small,the unconfined compressive and tensile strength of the mixture with recycled aggregates will be slightly higher than that of the un-doped recycled aggregate for 7 days.The strength and rigidity of the mixture increase with age,and early growth is more fast than the late.The compressive elastic modulus'of the cement stabilized aggregate mixture and cement stabilized recycled aggregate mixture disparities as the age increasing,but the result is opposite for the split resilient modulus.There is little difference for mechanical properties of mixture between cement stabilized crushed stone and cement stabilized recycled aggregate.Through the strength test and the rebound modulus test,it is concluded that there is a good linear correlation between the strength and the stiffness of the cement stabilized base material.Through the research on the curves between the age and the mechanical properties,it was found that the power exponent fitting is better.According to early mechanical performance data of the mixture,the power exponent model was established,which can provide some reference for the control of construction quality in the future.(4)Fatigue test datas are subject to Boolean function distribution.The fatigue performance of the cement stabilized crushed stone mixture without recycled aggregate is better than that of the mixture with recycled aggregate.The fatigue performance of the concrete mixed with recycled aggregate increases with the growing of the content of recycled aggregate.The fatigue performance of the cement stabilized aggregate mixture with the recycled aggregates is similar to that of the non-mixed recycled aggregates.In addition,compared with some related research on cement stabilized crushed stone base material fatigue test results at home and abroad,B value of the cement stabilized recycled aggregate mixture is close to results of crushed stone.it shows that the mixed material mixed with recycled aggregate can be used as pavement base materials in pavement base construction.