Study On The Pavement Performance Of Emulsified Asphalt Cold Recycled Mixture With Portland Cement

Currently most of the early construction of asphalt pavement has entered into the stage of maintenance and renovation,which is bound to bring a lot of bitumen waste.The cold recycling technology with emulsified asphalt can adequately address the problem of waste material,which can improve resource utilization and protect the ecological environment;therefore it is of important significance.This thesis,which relies on the projects of “mountain highway asphalt pavement cold recycling technology system" asphalt concrete pavement repair works in Guizhou Province Department of Transportation,studies the road performance of the cold recycling mixture with emulsified asphalt and cement.In the early work,this thesis makes a survey of the old road and analysis and evaluation of raw materials of the test section.The researches show that the road has produced different types of hazards,and propose specific repair remediation programs.After anglicizing the grade before and after RAP extraction,it is found that particles in the range of 9.5mm-0.6mm begin to agglomerate.Meanwhile,this thesis analyzes the mechanism and the influential factors of demulsification of emulsified asphalt theoretically.This thesis found that the lipophilic and hydrophilic groups of cationic emulsifier play an important role in the emulsification process of emulsified asphalt;the kind and amount of the emulsifier,the physical properties of aggregates and the construction conditions all have a certain impact in demulsification of emulsified asphalt;as a filler,cement has a certain influence on the structure and strength of recycled mixture,so it is analyzed theoretically from the hydration and powder effect of the cement,.This thesis finds that Superpave method is not suitable for cold recycled mixture ratio design.With modified Marshall Method,this thesis uses the optimum water content method to measure the optimum moisture content of recycled mixture,and uses the second method of forming standard Marshall Compaction specimen.It is found that,compared with the hot mix forming method,the quality of standard Marshall specimen cold recycling is much less.Specimen is curing in a 60 ? oven with the blower device shut for 72 hours,which simulate the low-pressure steam curing.In the study on road performance,this thesis uses different cement content and RAP content to do the mixture ratio design of cold recycled and analyzes their impact on the mechanical properties,high temperature stability,low temperature crackresistance and water stability of cold recycled materials.The results show that: the addition of cement has a significant effect on the optimum moisture content of the cold recycling mixture,which improves the mechanical properties,high temperature stability and resistance to water damage ability of the regeneration mixture,but reduces the low temperature anti-cracks ability of recycled material;whereas the addition of RAP reduces the mechanical properties,high temperature stability and resistance to water damage ability of cold recycled mixture,but it can increase the low temperature anti-cracks ability of recycled material.Ensure the blend mechanical properties and pavement performance under the premise,combined with the economic principle of environmental protection.Therefore,this thesis suggests the best dosage of cement is2% and the best of RAP is 90%,considering the mechanical properties and pavement performance of the cold recycling mixture and combining the economic principle of environmental protection.