Study On The Influence Of Waste Incineration Bottom Ash Aggregate On The Mechanical Properties And Microstructure Of Recycled Concrete

With the continuous development of urbanization,the annual increase in the output of municipal household garbage and the continuous strengthening of public awareness of environmental protection,the method of disposing of municipal household garbage by means of landfill has been gradually abandoned,and the technology of incineration and power generation of municipal household garbage has become the main method of disposing more and more municipal garbage.As an inevitable by-product of waste incineration,the waste incineration ash will also increase rapidly,which will bring about a series of environmental problems.This article adopts the method of net cement slurry wrapped slurry treatment for waste incineration bottom ash pretreatment,using X-ray diffraction(XRD)and scanning electron microscope(SEM)to study the waste incineration bottom ash handling internal physical properties,chemical composition,and after the change of microstructure,from two aspects of macroscopic mechanics and microscopic structure to explore the mechanism of concrete strength changes.At the same time,by using different proportions of municipal solid waste incineration ash to replace natural aggregate,the best replacement rate of solid waste incineration bottom ash that meets the mechanical properties and has environmental value is obtained,which provides a theoretical basis for the further application of solid waste incineration bottom ash in the construction industry.The main conclusions of this study are as follows:(1)Microscopic analysis shows that the surface of the bottom ash particles is not only rough and has many holes,but also has many micro holes.At the same time,the crystal laps are loose and the crystal gap is large.The microscopic properties of the porous material determine the physical properties of the substrate,such as low apparent density,high water absorption and porosity,and low self-strength.(2)After the treatment of cement paste,many pits and microscopic holes on the surface of the sample of waste incineration bottom ash after slurry coating are filled with cement slurry,which makes the surface of the bottom ash more flat and the structure of the bottom ash more compact after treatment,thus significantly improving the physical properties of the waste incineration bottom ash.The results show that the cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cementcement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement cement(3)The compressive strength,bending strength and splitting tensile strength of concrete show an overall trend of decline with the increase of replacement rate of recycled concrete aggregate.The mechanical properties of recycled concrete prepared from incinerated bottom ash after treatment have been improved greatly.On the basis of considering both mechanical properties and environmental protection requirements,it is concluded that the best replacement rate for natural coarse aggregate should be75%.It has better mechanical properties and social benefits when the bottom ash is replaced by 75% of the natural aggregate after treatment.It not only recycles and utilizes the waste incineration bottom ash greatly,but also retains good mechanical properties.(4)Cross-section analysis shows that the reason for the low coagulation strength of recycled aggregate prepared from waste incineration base ash is the insufficient strength of the base ash itself,and the interfacial transition zone is not the weakest link of recycled concrete.The mechanical properties of recycled concrete can be improved by effectively improving the strength of the waste incineration base ash after slurry treatment.(5)The leach toxicity index of recycled concrete prepared from waste incineration bottom ash conforms to the national standard,but the impact of heavy metals on the environment can be further reduced after the slurry treatment of the waste ash aggregate,making the recycled concrete from waste incineration bottom ash become a more environmentally friendly building material.