石墨尾矿砂沥青混合料水稳定性能研究

Study on the Water Stability Performance of Graphite Tailing Sand Asphalt Mixes

为探究石墨尾矿砂掺量对沥青混合料的水稳定性能的影响规律,以石墨尾矿砂替代传统细集料制备沥青混合料,设计体积掺量为机制砂10%~80%的石墨尾矿砂沥青混合料,并加入2种界面改性剂,即添加质量分数为0.6%的抗剥落剂和0.4%硅烷偶联剂以提高石墨尾矿与沥青的黏附性,通过水洗脱法评价细集料与沥青的黏附性以及界面改性剂对黏附性的提升效果。最后通过浸水马歇尔试验和冻融劈裂试验,分析不同体积掺量的石墨尾矿对沥青混合料水稳定性的影响,并对不同类型界面改性剂的改善效果进行评价。结果表明,石墨尾矿砂抗水剥落能力低于机制砂,石墨尾矿砂的剥落率为82.23%,机制砂为59.93%;沥青混合料水稳定性随着石墨尾矿砂掺量的提高逐渐降低;马歇尔稳定度随着石墨尾矿砂掺量的增加而先升高后降低;2种界面改性剂均可有效改善提升石墨尾矿砂与沥青的黏附性,未使用界面改性剂时石墨尾矿砂的最大掺量为30%,加入抗剥落剂后石墨尾矿砂最大掺量提升到40%,加入硅烷偶联剂后石墨尾矿砂最大掺量提升到50%。研究结果表明,石墨尾矿砂可以替代机制砂作为沥青混合料的骨料使用。

In order to investigate the effect of graphite tailing sand blending on the water stability performance of asphalt mixes,this work used graphite tailing sand to replace traditional fine aggregate in the preparation of asphalt mixes,and designed asphalt mixes with graphite tailing sand blending 10%to 80%by volume of mechanized sand,and two interface modifiers were added,with a mass fraction of 0.6%anti-spalling agent and 0.4%silane coupling agent to improve the adhesion of graphite tailings to asphalt.The adhesion of fine aggregates to asphalt and the effect of interface modifiers on adhesion enhancement were evaluated by water elution method.Finally,the effect of graphite tailings with different volume admixture on the water stability of asphalt mixture was analyzed by water immersion Marshall test and freeze-thaw splitting test,and the improvement effect of different types of interface modifiers was evaluated.The test results showed that the flaking rate of graphite tailing sand was 82.23%,which was lower than that of 59.93%of the mechanism sand;the water stability of asphalt mixture gradually decreased with the increase of graphite tailing sand admixture;Marshall stability increased and then decreased with the increase of graphite tailing sand admixture.Both interface modifiers can effectively improve the adhesion of graphite tailing sand to asphalt.The maximum admixture of graphite tailing sand was 30%without the use of interface modifier,and the maximum admixture of graphite tailing sand was increased to 40%with the addition of anti-exfoliation agent,and to 50%with the addition of silane coupling agent.The results of this study indicate that graphite tailings sand can be used as an aggregate for asphalt mixes instead of mechanized sand.