Study On Application Of The Steel Slag In Asphalt Concrete Of Core-wall

Solid waste about the steel slag is one of the main sources of solid pollution.In order to improve the utilization ratio of steel slag and solve the problem of regional ecological environment pollution.The steel slag is used as the mineral aggregate in the asphalt concrete of core-wall in this paper.Researched the difference of basic physical properties about the steel slag,natural?acid?gravel,alkaline crushed stone.Analyzed the difference of the bond property of the asphalt mortar made of the steel slag powder,cement,mineral powder mix with asphalt.Evaluated of the adhesion grade of the steel slag,natural gravel,alkaline crushed stone by the improved boiling method.Optimized the optimum mix proportion of the steel slag asphalt concrete by orthogonal test.To determine the difference of the mechanical properties about the steel slag,natural gravel,alkaline crushed stone asphalt concrete respectively carried out the water stability,tensile,bending,compression and permeability tests.Studied the long-term water stability of the steel slag asphalt concrete by freeze-thaw splitting test,long-term water stability test,swelling test.Analyzed the stress-strain relationship of it by static three axial test.The main conclusions are as follows:?1?The steel slag belongs to the basic aggregate,the alkalinity modulus is 3.93;the alkali value is 1.60.The crushing value of steel slag is 3.3%,the durability is about 2.4%,and the durability of steel slag sand is about 5.3%,which is better than that of natural gravel and alkaline crushed stone.?2?To extend the time of boiling to test the adhesion of the materials with asphalt,in the 12¹5min,can significantly distinguish the adhesion property is as follows:steel slag>alkaline gravel>natural gravel,so when boiled 3min cannot judge asphalt adhesion difference with the steel slag and other materials,the boiling time should be extend to 12¹5min.The adhesive strength of the same concentration of asphalt mortar is:steel slag powder>cement>limestone powder.?3?Based on the analysis of the chemical composition of steel slag,the content of f-CaO in steel slag is 1.61%of the total mass.The particle size of steel slag is more than 4.75mm,it can be soaked for 4 days,and the particle size is less than 4.75mm,it can be stabilized for 12 days.The 3-day expansion of steel slag asphalt concrete made of steel slag after soaking treatment is about 0.27%,it is indicated that a small amount of f-CaO has little effect on the expansion of steel slag.?4?Through orthogonal test,it is recommended that the mix ratio of steel slag asphalt concrete is as follows:the ratio of asphalt to stone is 7.5%,the amount of filler is about 10%,and the gradation index is about 0.39.The water stability,flexural strength and compressive strength of the steel slag asphalt concrete are better than the natural gravel asphalt concrete and the basic gravel asphalt concrete.the Impermeability weaker than natural gravel,gravel basic asphalt concrete,but meet the engineering requirements of<1×10^-8cm/s.After 6 freeze-thaw cycles of splitting tensile strength ratio can reach 78.25%,the long term water stability is better.After 60 days in water,the volume expansion rate slows down and the volume tends to stabilize.The parameters of Duncan Chang model accord with the stress-strain characteristics of hydraulic asphalt concrete.The results show that it has a certain application value in the asphalt concrete with rolling core wall.