不同金属添加剂对沥青混合料路用性能及微波愈合特性的影响分析

基于微波加热的沥青混合料自愈合是一种有效的沥青混合料裂缝愈合技术。这类沥青混合料通常含有促进微波加热的金属添加剂,为探究不同金属添加剂对沥青混合料愈合特性的影响,对比了不含金属添加剂的普通沥青混合料以及添加钢丝棉纤维、钢刨花和钢渣的沥青混合料的微波加热效率和裂缝愈合能力。微波加热效率通过相同微波加热时间下沥青混合料的升温速度来评价。裂缝愈合能力采用微波愈合前后沥青混合料半圆弯曲试验峰值荷载的比值作为评价指标。此外,不同金属添加剂对沥青混合料路用性能的影响采用车辙试验、小梁弯曲试验、浸水马歇尔试验以及冻融劈裂试验来进行评价。试验结果表明:添加钢丝棉纤维、钢刨花以及钢渣后沥青混合料的微波加热升温速率相比普通沥青混合料分别提高了22.28%、16.20%和39.49%,裂缝愈合能力相比普通沥青混合料分别提高了9.44%、3.78%和16.99%。钢丝棉纤维、钢刨花和钢渣3种金属添加剂可以不同程度地改善沥青混合料的路用性能。

Effect of different metal additives on road performance and microwave self-healing characteristics of asphalt mixtures

Microwave heating is an effective technique for inducing self-healing mechanism of asphalt mixtures in crack healing. This kind of asphalt mixtures usually contains metal additives to promote microwave heating. In order to explore the effect of different metal additives on the self-healing characteristics of asphalt mixtures, the microwave heating efficiency and crack healing ability of ordinary asphalt mixture without metal additives and asphalt mixtures with steel wool fiber, steel shavings or steel slag were compared in this study. The microwave heating efficiency of different mixtures was evaluated by the heating rate of different asphalt mixtures under the same heating time. Meanwhile, the crack healing ability was evaluated by the ratio of peak load of semi-circular bending test of asphalt mixtures before and after microwave heating. In addition, the rutting test, trabecular bending test, immersion Marshall test and freeze-thaw splitting test were carried out to evaluate the influence of different metal additives on the road performance of the respective asphalt mixture. The results showed that the microwave heating rate of the asphalt mixtures increased by 22.28%, 16.20% and 39.49% compared with normal asphalt mixture without additives, and the crack healing ability increased by 9.44%, 3.78% and 16.99% after adding steel wool fiber, steel shavings and steel slag, respectively. Therefore, the road performance of asphalt mixtures can be improved with varying degrees by adding these 3 metal additives.