Valuation Of Particle Group Strength And Study On Gradation Changes About Cold Recycled Mixture

Cold recycling technology of asphalt pavement can effectively raise the utilization rateof resources and protect environment. It also has the remarkable economic, social andenvironment benefits. Today, cold recycling technology is widely applied in the maintenanceof asphalt pavement. Cold recycling technology is applied in road construction. Cold recycledmixture could crush in the compaction process, which results in gradation changes of coldrecycled mixture. At present, research about this problem is less.The purpose of this paper isto investigate the gradation changes condition of cold recycled mixture after the indoorcompaction by indoor compaction test. By using the discrete element method, this paperanalyses the particle breakage phenomenon in the compaction process that results in gradationchanges of cold recycled mixture.Firstly, this paper studies cold recycled mixture gradation changes in the indoorcompaction process, which finds that cold recycled mixture particle breakage occurs in theindoor compaction process. The particle breakage mainly concentrates in particle size rangefrom9.5mm to26.5mm, which results in gradition changes of cold recycled mixture.Secondly, the old lime splitting strength is tested on the basis of old road investigate. By usingPFC2Dsoftware, this paper simulates the old lime splitting tensile strength test and putsforward to using old lime parallel bond strength to evaluate particle group strength of coldrecycled mixture. Then, by using PFC2Dsoftware, this paper sets up discrete element modelabout cold recycled mixture structural layer and simulates its compaction process. It finds thatwith the rolling compaction times increasing, namely the increasing number of cold recycledmixture particle breakage, which leads to gradation changes of cold recycled mixture.Finally, this paper puts forward the target gradation range when basement layer of secondroads and less uses cold recycled mixture. And it puts forward a measure or method thatcorrects target gradation. The compressive strength, splitting tensile strength, compressivemodulus and flexural strength of cold recycled mixture whose stabilizer is cement-lime areresearched. The results show that at a certain age and cement content, the compressive strength, splitting tensile strength and flexural strength of cement-lime cold recycled mixturewill decrease with lime content increasing. When content of cement and lime is certain, thecompressive strength, splitting tensile strength and compressive modulus of cement-lime coldrecycled mixture will increase with age increasing.The above study results could enrich cold in-place recycling technology of low graderoad. It provides certain reference value for cold recycling construction technology. And it hascertain theoretical and practical significance.