Research On Preparation Of Recycled Concrete Curb Stone By Construction Waste

In recent years,with the acceleration of urban construction and the transformation of old cities in China,a large amount of construction waste not only destroys the ecological environment,but also wastes natural resources.The use of construction waste to prepare high-quality recycled coarse aggregate,and the engineering application of recycled concrete products prepared on the basis of this,not only saves natural resources,but also protects the ecological environment,which meets the requirements of building a beautiful China and creating a good production and living environment for the people in the 19 th National Congress.However,among the construction wastes produced in China,the proportion of brick-concrete construction waste is high,the content of brick has a significant impact on the performance of recycled coarse aggregate,and the various physical properties of recycled coarse aggregates decreased significantly with the increase of brick content.Therefore,in order to ensure the quality of recycled coarse aggregate and improve the resource utilization rate of construction waste,the research and development of brick-concrete separation technology and high value-added recycled concrete products are extremely urgent.The brick-concrete separation technology in construction waste and the preparation technology of recycled concrete curbs based on experimental research were studied in this paper.The main research contents include: separation effect of brick-concrete separation technology by extrusion method,effect of recycled coarse aggregate with different quality on the performance of recycled concrete for curbs,optimization of mix proportion of recycled concrete used in curbs,and analysis of performance and economy of recycled concrete curbs,etc.The research indicates:(1)Brick-concrete separation effect of brick-concrete separation technology by extrusion method is related to the maximum particle size of the initial mixed aggregate.The larger the particle size is,the better the brick-concrete separation effect is.Brick content in the recycled coarse aggregate with a particle size of 16.0mm-31.5mm can be reduced from 50% to about 12% by the extrusion brick mixing technology.(2)The performance of recycled coarse aggregates with particle size of16.0mm-31.5mm prepared by extrusion brick-concrete technology can meet therequirements of Grade-II and grade-III recycled coarse aggregates.Extrusion separation-granular shaping regeneration coarse aggregate quality improvement technology can produce recycled coarse aggregate with brick content less than 2%,and its performance index meets the requirements of class-I recycled coarse aggregate.(3)The quality of recycled coarse aggregate has a significant effect on the working performance,mechanical properties and physical properties of the recycled concrete used for curbs.With the decrease of the recycled coarse aggregate quality,the amount of recycled concrete used for curbs is gradually increasing,and the less the amount of cementing material is,the greater the influence on the water consumption of recycled stone used for curbs is.With the improvement of the recycled coarse aggregate quality,the compressive strength and flexural strength of recycled concrete used for curbs are gradually increased,and the water absorption,frost resistance and salt freezing resistance are improved,which can meet the requirements of curb production technology.Among them,the properties of recycled concrete used for curbs prepared by Class-I recycled coarse aggregates are the closest to ordinary concrete.(4)The performance of recycled concrete curb is consistent with the relevant provisions of "Concrete Curb Stone"(JC/T 899-2016).The unilateral cost of recycled concrete curbs prepared by class-I recycled coarse aggregate is about 70 yuan lower than ordinary concrete curbs,which has obvious economic advantages.The brick-concrete separation technology of construction waste is taken as the core research content,and the preparation technology of high-quality recycled coarse aggregate and recycled concrete curbs is studied in detail by brick-concrete separation technology in this paper.It is of great significance for the preparation of recycled coarse aggregate and the application of recycled concrete,which is conducive to the resource utilization of construction waste.