封装修复剂作用下沥青混合料反射裂缝的自愈合

Self-healing of reflective cracks in asphalt mixtures by the action of encapsulated agents

封装修复剂可以延缓沥青混合料中反射裂缝的发展,并且有助于延长沥青表面的养护周期。当沥青出现裂缝破坏时,胶囊膜会发生破裂,其中的修复剂会释放到裂缝附近。本试验研究揭示了当沥青受到循环荷载作用时,油相从胶囊中释放出来的量及其对沥青自然裂缝自愈合能力的提高作用。通过力学和化学测试相结合的方法发现,大多数胶囊都能抵抗沥青的拌和和压实,研究还发现,在多孔沥青中,油相会在沥青的服役寿命内逐渐释放出来,而在密级配沥青混合料中,油相则会在裂缝开始出现时就释放。结果表明,沥青的级配是设计沥青基自修复胶囊强度的关键参数,此外,多孔沥青和沥青玛蹄脂碎石的自愈合效率要高于密级配沥青混合料。最后,发现在沥青路面的服役寿命中存在一个胶囊能够最有效地修复现有裂缝损伤的时刻。

Encapsulated healing agents may delay the growth of reflective cracking in asphalt mixtures and contribute to delay the maintenance of asphalt surfaces.When crack damage appears in the asphalt,the capsules membrane ruptures,and the healing agents are released in the vicinity of the cracks.This experimental research shows the rate at which the oil is released from the capsules when the asphalt is exposed to cyclic loading and its capacity to improve the natural crack self-healing capacities of the asphalt.Using a combination of mechanical and chemical testing,it was found that most of the capsules resist asphalt mixing and compaction.It was found that in porous asphalt,the oil is released gradually during the lifetime of the asphalt,while in dense asphalt,the oil is released at the time when cracks start appearing.This is an indication that the gradation of asphalt is a critical parameter to design the strength of capsules for asphalt self-healing.Furthermore,the self-healing efficiency of capsules is higher in porous and stone mastic asphalt than in dense asphalt mixture.Finally,it has been found that there is a moment in the lifetime of an asphalt road when the capsules are most effective to self-heal the existing crack damage.