橡胶沥青混合料SAC-13级配空隙率变化分析

Air Void Variation of Asphalt Rubber Mixture Grade SAC-13

摘要:

在普通沥青的多碎石沥青混凝土（SAC）设计的基础上，以空隙率为研究变量，采用固定油石比，再微调级配的方式，深入对比了SAC 13级配变化的普通沥青和橡胶沥青混合料的空隙率影响规律.结果显示：对于普通SAC 13沥青混合料，油石比每增加0.5%，空隙率减小1%~1.5%，随着9.5~13.2 mm粗集料含量增多，4.75~9.5 mm粗集料含量减少，混合料粗集料间隙率呈递减之势；对SAC橡胶沥青混合料，建议9.5 mm以上集料用量范围限定在30%~45%之间，4.75~9.5 mm集料用量范围限定在20%~40%之间，且4.75 mm以上粗集料总用量应达到60%以上，2.36~4.75 mm集料含量不宜高于10%，且不宜使用过多矿粉；同样目标空隙率下，SAC 13橡胶沥青混合料的粗集料掺量应略低于普通沥青混合料；SAC 13橡胶沥青混合料中当2.36~4.75 mm集料含量达到8%以后，随着该档料用量的增加，空隙率增幅明显高于普通沥青混合料，需严格控制此档料含量.

Abstract:

Based on the design of stone asphalt concrete(SAC) mixture of plain asphalt, a comparative study was made of the influence law of air void of SAC 13 grading on plain asphalt and asphalt rubber mixture with the air void as the variable by setting the asphalt content first and then fine tune grading. The result shows that for normal SAC 13 mixture, when the oil aggregate ratio increases by 0.5% each time, air void will decrease by 1% to 1.5% instead. With the increase of 9.5 ~ 13.2 mm coarse aggregate content, 4.75 ~ 9.5 mm aggregate content and the void of coarse aggregates(VCA) will decrease by degrees. With regard to the SAC asphalt rubber mixture, aggregate content (＞9.5 mm) is recommended to be within 30% ~ 45% and the 4.75 ~ 9.5 mm be within 20%~40%, in addition, the total volume of coarse aggregate (＞4.75 mm) is proposed to be over 60%, 2.36 ~ 4.75 mm aggregate content is not proposed to be over 10%, and mineral powder to be used little. With the same objective void, SAC 13 asphalt rubber mixture of coarse aggregate content is proposed to be slightly less than normal SAC mixture. As for SAC 13 rubber asphalt mixture, when the content of 2.36 ~ 4.75 mm aggregate reaches 8%, void increases much more distinctively than that of normal SAC mixture, so the content of this grade should be strictly controlled.