Research On Environment And Economic Benefits Of Steel Slag Asphalt Pavement With Different Pretreatment Methods

In order to solve the shortage of natural aggregate and surplus steel slag resources but not fully utilized,a number of studies have verified the feasibility of using steel slag as pavement aggregate,and the relevant test sections have also been constructed,indicating that the performance of steel slag pavement is good.Few studies have carried out systematic quantitative analysis on the environmental and economic benefits of steel slag pavement.Whether the pavement economy is the first choice for actual engineering decisions at present,and identifying the pavement environmental impact can promote energy conservation and emission reduction and achieve sustainable development of the pavement.Therefore,the environmental and economic benefits of partially replacing aggregate with steel slag for pavement mixture are analyzed.First of all,through the investigation of the steel slag pavement structure and check the structure under the traffic volume to determine: cement stabilized macadam base,bottom base,respectively mixed with the volume ratio of macadam is 60:40 steel slag;Steel slag asphalt concrete mixes steel slag and gravel into the upper layer,middle surface layer and lower layer according to the volume ratio of 60:40.The inventory required for Life Cycle Analysis(LCA)and Life Cycle Cost Analysis(LCCA)of steel slag pavement was constructed based on literature review and investigation methods.The energy consumption and carbon emission of the traditional pretreatment process(natural aging)and accelerated treatment process(pressurized heat stuffing)were calculated.In addition,the cost of unit personnel,materials,machinery and unit pollutant treatment required for road surface LCCA analysis were collected.Secondly,based on the engineering quota and the mechanical team fee quota,the LCA model of cement stabilized steel slag gravel base and steel slag asphalt surface based on Excel was constructed.Taking cement water-stabilized crushed stone and asphalt surface without steel slag as reference cases,the environmental impact of steel slag presenting in the base and surface of different treatment processes was compared.The results show that during the construction period,compared with the cementstabilized macadam base,the emission reduction benefit of the cement-stabilized macadam base with hot and stuffy slag is less than that of the base with natural aging slag.Similarly,the energy saving and emission reduction benefit of adding aging slag to asphalt surface or asphalt pavement is better than that of adding hot and stuffy slag.Then,the construction cost of steel slag pavement during the construction period was quantified by the quota,and the carbon emission quantified by LCA was monetized by the social willingness payment theory.Finally,the environment-economic benefit of steel slag pavement was comprehensively quantified by the cost-benefit index.The results show that compared with the structural layer without steel slag,the use of aging slag in cement-stabilized macadam base layer,cement-stabilized macadam base layer,and the use of aging slag and hot slag in asphalt surface layer or asphalt pavement have environmental and economic benefits.Finally,although the energy saving and emission reduction benefits of using hot and stuffy slag in cement stabilized macadamite and asphalt concrete are not very good,the advantages and disadvantages of aging slag and hot and stuffy slag are analyzed:aging slag needs to occupy land,the production environment of steel mill is dirty and messy,and sometimes the stability is not qualified.The treatment time of hot and stuffy slag is 2h,the treatment area is closed and the dust is removed,and the volume of steel slag is stable.Therefore,the selection of hot and stuffy slag or aging slag is based on the joint decision of steel slag treatment and road construction department.