钢渣沥青混合料试件重金属元素浸出行为及影响因素分析

Analysis of Leaching Behavior and Influencing Factors of Heavy Metal Elements from Steel Slag Asphalt Mixture Specimens

为探讨钢渣沥青混合料路面重金属元素浸出行为和影响因素,以萍钢钢渣设计的钢渣混合料和钢渣沥青混合料试件为研究对象,配制模拟当地酸雨pH值的浸取剂,通过恒温振荡器(300 r/min)振荡6 h+静态浸泡18 h的混合料抽出方式,采用ICAP 7200 ICP-OES测试浸出液重金属元素。以3种胶结材料、3个沥青用量、3个温度为影响因素对设计的钢渣混合料进行正交试验,应用极差与方差分析法对浸出行为和影响因素进行分析。研究结果表明:萍钢钢渣混合料试件浸出液检测出了Fe、Mn、Cu等3种重金属元素;无胶结材料的钢渣混合料重金属元素浸出浓度最大,普通70号沥青混合料试件次之,SBS改性沥青混合料试件最小;对于同种沥青混合料试件,随着沥青用量的增大,重金属元素浸出浓度减小;温度对重金属元素浸出行为不完全相同,随着温度的升高,Fe、Cu元素浸出浓度增大,但Mn元素呈现先降低再升高的趋势。钢渣沥青混合料试件重金属元素浸出浓度的影响因素也有不同:影响Fe、Cu元素浸出浓度的主次顺序为温度>沥青用量>胶结材料;影响Mn元素浸出浓度的主次顺序为沥青用量>温度>胶结材料。研究成果对制定钢渣沥青混合料试件重金属元素浸出浓度试验和设计钢渣沥青混合料路面有参考价值。

In order to explore the leaching behavior and influencing factors of heavy metal elements on steel slag asphalt mixture pavement, the steel slag mixture and steel slag asphalt mixture samples designed by Pinggang steel slag are taken as the research objects. The leaching agent is prepared to simulate the pH value of local acid rain, and the mixture extraction method is carried out by the constant temperature oscillator(300 r/min) oscillating for 6 h+ static soaking for 18 h. The heavy metal elements in the leaching solution are measured by ICAP 7200ICP-OES.With three cementing materials,three asphalt dosages,and three temperatures as influencing factors,orthogonal experiments are carried out on the designed steel slag mixture,and range analysis and variance analysis methods are used to analyze the leaching behavior and influencing factors.The results show that three heavy metal elements Fe,Mn and Cu are detected in the leaching solution of Pinggang steel slag mixture.The steel slag mixture of uncemented material has the highest heavy metal elements leaching concentration,followed by ordinary 70 asphalt mixture,and SBS modified asphalt mixture has the lowest leaching concentration.For the same asphalt mixture,the leaching concentration of heavy metal decreases with the increase of asphalt dosage.Temperature leaching behavior of heavy metal elements is not completely the same,with the increase of temperature,leaching concentration of Fe and Cu increases,but Mn shows a trend of decreasing first and then increasing.The factors influencing the leaching concentration of heavy metals in steel slag asphalt mixture are also different:the primary and secondary order of influencing the leaching concentration of Fe and Cu is temperature>asphalt dosage>cementitious material;the primary and secondary order of influencing Mn leaching concentration is asphalt dosage > temperature > cementitious material.The research results have reference value for the formulation of heavy metal leaching concentration test of steel slag asphalt mixture and the design of steel slag asphalt mixture pavement.