Mechanistic Studies of Asphalt Aging Aimed at the Discovery of Anti-aging Additives

今天为市政、省和国家机构建造的沥青路面很少能像25年前那样持久。一些地区的寿命缩短了50-60%（年度报告，安大略审计长，2016年），主要是由于不良的做法和材料。减少的原因是交通繁忙、异常天气（夏季/冬季极端气温）、工程处工作人员缺乏知识导致使用不适当的规格，以及通过不正确和/或不负责任地使用某些回收材料来“绿化”我们的道路。在整个加拿大，价值约1200亿加元的道路处于公平、贫穷或非常贫穷的状态（加拿大基础设施报告卡，2016年）。 自2004年以来，我的团队制定了严格的规范标准，并在安大略和国外的众多用户机构中实施，取得了很大的效果。我们现在需要研究如何使用有效的添加剂来减轻老化，以进一步减少开裂。 我们的短期目标是了解如何通过监测环境温度和低温下沥青中蜡、树脂和沥青质的沉淀来更好地评估热可逆老化。在这一领域的第一次，我们将使用创新的红外光谱法开发监测原油中的蜡和沥青质沉淀，以测量沥青中的蜡和沥青质沉淀。 我们将研究凝胶的形成，通过测量沥青的性质，已被化学老化到不同程度的复杂的流变学方法。与目前用于规范分级的因素相比，定义凝胶化开始的因素将提供更准确的测量沥青何时变得易于开裂。 我们还将研究不可逆的老化，以增加证据，长期以来在文献中的争议，沥青如何与氧气反应，并随着时间的推移硬化。我们将使用氧-17核磁共振光谱，这在这个领域还是第一次，以及更传统的质子，碳-13和硅-29光谱，在一维和二维。我们将在可行的情况下使用同位素富集保护基团。 作为长期目标，我们将评估使用防蜡剂、分散剂、抗氧化剂和非常规基础沥青来减缓老化，并使用光谱、热和流变分析技术来评估我们创新的抗老化添加剂的有效性。 这项研究计划将减少路面开裂的痛苦，并提供一个更可持续的，耐用的道路基础设施。联邦、省和市政府以及加拿大和国外的公众将在未来的基础设施支出上节省大量资金，减少旅行延误，改善道路安全。嵌入式培训计划将为学生提供一套非常理想的可转移技能和抢手的知识，这将使他们在劳动力中具有竞争优势。

Asphalt pavements constructed for municipal, provincial and national agencies today rarely last as long as they did 25 years ago. Some regions have seen lifespans shrink by as much as 50-60% (Annual Report, Auditor General of Ontario, 2016), largely due to poor practices and materials. The decline is due to heavier traffic, anomalous weather (extreme summer/winter temperatures), lack of knowledge among agency staff leading to the use of inadequate specifications, and the “greening” of our roads through the incorrect and/or irresponsible use of certain recycled materials. Across Canada, ~$120 billion-worth of roads are in fair, poor or very poor state (Canadian Infrastructure Report Card, 2016). Since 2004, my group has developed rigorous specification standards and implemented them to great effect in numerous user agencies in Ontario and abroad. We now need to investigate how to mitigate aging with effective additives to further reduce cracking. Our short-term objective is to understand how to better assess thermoreversible aging by monitoring the precipitation of waxes, resins and asphaltenes in asphalt at ambient and cold temperatures. In a first for this sector, we will use innovative infrared spectroscopy methods developed to monitor wax and asphaltene precipitation in crude oils to measure wax and asphaltene precipitation in asphalt. We will study gel formation by measuring properties for asphalt that has been chemically aged to varying degrees with sophisticated rheological methods. Factors defining the onset of gelation will provide a more accurate measure of when asphalt becomes prone to cracking than those currently used for specification grading. We will also study irreversible aging to add evidence to longstanding disputes in the literature on how asphalts react with oxygen and harden over time. We will use oxygen-17 nuclear magnetic resonance spectroscopy, again for the first time in this sector, together with more conventional proton, carbon-13 and silicon-29 spectroscopy, in both one and two dimensions. We will use isotope enriched protective groups where feasible. As a long-term goal, we will evaluate the use of wax inhibitors, dispersants, antioxidants and unconventional base asphalts to mitigate aging, and use the spectroscopic, thermal and rheological analysis techniques to assess the effectiveness of our innovative anti-aging additives. This research program will reduce cracking distress in pavements and provide a more sustainable, durable road infrastructure. Federal, provincial and municipal governments, as well as the general public in Canada and abroad, will achieve enormous savings on future infrastructure expenditures, reduce travel delays and improve road safety. The embedded training program will give students a highly desirable set of transferable skills and sought-after knowledge that will give them a competitive edge in the work force.