Research On Early Strength Recycling Technology Of Waste Cement Concrete Pavement Materials

At present,the road in the reconstruction and maintenance process will produce a lot of waste recycling materials,waste a lot of resources,how to achieve the recycling of old pavement waste has been the focus of domestic and foreign road departments;in addition,in some urban road maintenance construction process,the time of traffic closure is too long,which will lead to traffic congestion.In order to effectively solve the above problems,early strength cold regeneration technology is adopted to realize waste utilization and achieve the purpose of opening traffic quickly.In this paper,combined with the characteristics of waste recycled materials,the mix proportion design,road performance and construction characteristics of early strength recycled base mixture of cement base are studied.The implementation and technical evaluation of cold recycling solid project are carried out,and the economic and social benefits are analyzed.Firstly,test and analyze the compressive strength of recycled base mixture under different waste recycling content,and determine the best target mix proportion;secondly,through the unconfined compressive strength,splitting strength,modulus of resilience tests to study the mechanical properties of recycled mixture,analyze its anti cracking and water stability performance;on this basis,through indoor simulation test to study early strength regeneration The strength development law of base mixture increases with the increase of placing time in different temperature range.Finally,through the paving entity project to observe the use effect of cold recycled mixture,further determine its construction technology;at the same time,analyze and compare the economic,social and environmental benefits of recycling technology.The research results show that the indoor test is carried out by mixing different proportions of crushed materials.The research shows that the crushed materials are well graded when the content of crushed materials is 100%.According to the strength test results,the target mix ratio of recycled base materials is recommended to be 10-25mm crushed stone:5-15mm crushed stone:stone powder=35:35:30,cement dosage is 3.5%,the best water content and maximum dry density of the mixture are 7.5%and 2.110g/cm~3respectively.The applicability of basic road performance of cold recycled materials is briefly analyzed.The test results show that the road performance of cold recycled materials meets the requirements.The1d strength of specimens with 8%and 12%early strength agent basically reaches 7d strength without adding amount.Therefore,it can be concluded that the traffic can be opened one week in advance by adopting early strength cold recycling technology.According to the change of early strength agent dosage under different temperature and time,the test results show that the dosage of early strength agent should be controlled at about 8%under the condition of high temperature in summer and transportation time is more than 2h,in order to ensure the strength of mixture at room temperature,the content of early strength agent can be properly improved.Through the paving of cold recycled mixture,it shows that the early strength cold recycled mixture has good road performance and application effect when it is used in the reconstruction and expansion project of Kunshan airport road.Cold recycling technology has the advantages of simplifying construction technology,saving raw materials,shortening construction period,protecting environment and providing favorable working environment.