The Influence Of Recycled Concrete Gradation For Cement Stabilized Macadam Material

Recycled aggregate is used in road subgrade and pavement because of its good mechanical properties and road performance..But in practical engineering application.There are many differences in the nature of recycled aggregate due to the different sources of recycled aggregate.such as the differences in gradation.In order to study the performance of recycled mixture better.for improving its stability.This research has studied the influence of recycled aggregate gradation on the performance of recycled aggregate base course materials systematically.The main contents of the research are as follows:1.Screening of three kinds of aggregate,water absorption,apparent density and crushing value test.2.According to the standard requirements,A total of 7 recycled cement stabilized materials were designed and tested for their mechanical properties and pavement performance.3.testing its long-term behaviors inclouding air shrinkage and temperature shrinkage property,including mechanical attrition treatment and water washing treatment.4.In order to improve the ability of anti contraction.The study has used two different methods of to deal with the recycled aggregate.Shrinkage properties of recycled materials stabilized after treatment were studied.The results of the study are as follows:1.The two kinds of recycled aggregate from different sources have different surface cement mortar quantity,which caused the differences in physical properties of them.This is the main reason for the difference in natural aggregate and recycled aggregate.2.According to the mechanical properties test results show that the best recycled aggregate content is between 40%~60% in the project.The cement content should be controlled at about 5%.At this time,the 7 day unconfined compressive strength of each gradation can meet the requirements of the specification.which can also achieve the purpose of saving project cost.3.Road performance results show that dry shrinkage,temperature shrinkage and water loss rate will increase with the increase of the amount of recycled aggregate.The increasing of shrinkage and water loss rate is not conducive to practical engineering.So it is necessary to pretreat the recycled aggregate to improve the anti shrinkage ability.4.The recycled aggregate is treated with two different treatment methods,Through the test results can be found.After treating the recycled aggregate,which can not only improve unconfired compression strength but also reduce shrinkage to a certain degree.it is meaningful to the project effectively.