Study On Recycling And Application In Urban Main Roads Of Concrete Construction Waste

With the rapid development of infrastructure construction in our country,the demand for natural sand and other materials is increasing,while it is not renewable for a short time,and the contradiction between supply and demand and the environmental damage are becoming more and more prominent.At the same time,in the process of urban construction,a large amount of construction waste will be produced,it can account for 30%to 40%of the total amount of municipal waste.The treatment of construction waste using buried and opencast disposal will pollute the soil,air and water,which not only causes the waste of resources,but also destroys the environment.A large number of literatures show that construction waste has high value of recycling.Especially,recycled aggregate of concrete building waste can be used instead of natural sand as aggregate.However,in the recycling process of concrete building waste,the yield of recycled coarse aggregate is difficult to control,and the proportional of regenerated fine aggregate is more,so it can not be used well.Due to the lack of relevant codes for building waste recycling in China,it brings great difficulties to its engineering application.By studying the regeneration of concrete construction waste,a regeneration technology with high added value for building waste recycling is proposed.And it is used in the base of urban expressway.Contrast the?Technical Guidelines for Construction of Highway Roadbases?(JTG/T F20-2015)and?Gode for construction and quality acceptance of road works in city and town?(CJJ1-2008).The design method of lime-fly ash stabilized recycled aggregate is determined.In order to further increase the utilization ratio of regenerated fine aggregate,this paper studies the use of the recycled pavement brick for urban road.Through the study of the performance of recycled pavement brick cement mortar,the feasibility of the regenerated fine aggregate in place of the natural sand to prepare the recycled pavement brick is analyzed,and the laboratory mix ratio is determined.The hydration mechanism of recycled aggregate and cement was analyzed by XRD,SEM and other microscopic characterization methods.Research shows that urban concrete construction waste can achieve zero emissions regeneration technology,maximizing and reducing resource waste.The recycled coarse aggregate can be mainly used in the lime-fly ash stabilized recycled aggregate base of the main road of the city,and the design results of the?Technical Guidelines for Construction of Highway Roadbases?(JTG/T F20-2015)are better than?Gode for construction and quality acceptance of road works in city and town?(CJJ1-2008).In addition to the urban main road base,the regenerated fine aggregate can also be used in the urban road regenerative brick.When the cement content reaches 40%,it can meet the requirement of the strength grade of the C_C40road brick.Compared with the ordinary cement mortar Road tile index,the volume stability is fine,the frost resistance and the wear resistance are all meet the requirements.