Study On Frost Resistant Of Construction Waste Recycled Aggregate Concrete Curbs

Since the reform and opening up,urban construction has developed rapidly,which has caused more and more old buildings to be demolished,and the emission of construction waste has increased with each passing day.The continuous burglary of construction waste and construction waste around the city poses a serious threat to the environment in China.At the same time,the rapid development of transport infrastructure and the increasing demand for curbstones.As the most widely used building materials,concrete materials need a lot of sandstone.The contradiction between high-speed development of engineering construction and aggregate shortage is increasingly prominent.The rational use of construction waste in the preparation of recycled aggregates and the application of recycled concrete curbs can effectively alleviate the shortage of sand and natural environment pressure.In this paper,the basic properties of recycled aggregates for construction waste,as well as the frost resistance and practical application of recycled aggregate concrete curbs were studied.The study found that the brick rich in recycled aggregate particles and old cement mortar,and recycled aggregate surface roughness,cracks,resulting in recycled aggregate small apparent density,water absorption,crushing index and large amount of mud,with pre wetting and coating method and particle shaping can partly compensate for these defects.The curb is divided into artificial regenerated concrete manufactured by machine and dry recycled concrete made by machine.The replacement rate of recycled aggregate is 100%.The freeze-thaw method is used to make 50 freeze-thaw cycles.As the number of cycles increases,the surface of the specimen begins to become rough,and tiny micro-cracks begin to develop around the cell holes and small cracks.The quality of test pieces showed an upward trend,and the growth rate decreased after 25 cycles.This is mainly due to the large amount of water absorbed by the aggregates and the denuding effect of recycled concrete is not sufficient to counteract it.The quality of the dry hard recycled concrete slightly increases after a slight decrease.The internal structure of the specimen may be damaged by freezing and thawing.Sudden increase in pore connectivity will increase the water absorption quality of the specimen.The strength loss rates of plastic recycledconcrete and dry recycled concrete are 7.7% and 7.1% respectively,and the frost resistance is more than D50.The application of dry and hard recycled aggregate stone in practical engineering has been tested in winter,and its application effect is good.