基于微纳观测试的混凝土再生集料与沥青粘附特性、失效机理及增强研究

Due to its special surface structure and chemical composition, the adhesion between RCA and asphalt is extremely complicated, which makes the road performances of HMA-RCA (asphalt mixture containing RCA) is complicated as RCA content varies. The risk of potential early damage has created obstacles to large-scale reuse. Therefore, It is of key importance to reveal the particularity of adhesion of RCA/asphalt for improving the road performance of HMA-RCA. The micro-nano tests and macro-test is utilized as the main means in this project. The surface micro-morphology (SMM) and chemical composition of RCA will be quantitatively evaluated. The influence of chemical composition on RCA surface energy parameters and RCA/asphalt adhesion energy will be defined, further to explore the microscopic mechanism of chemical interaction on RCA/asphalt adhesion. The influencing factors and weights of aggregate/asphalt macroscopic adhesion strength will be investigated, and a refined model of SMM and adhesion strength will be established, further to reveal the microscopic mechanism of physical interaction of RCA/asphalt adhesion. The mechanism of adhesion failure caused by SMM attenuation, moisture and asphalt aging will be discussed. Finally, adhesion enhancement measures will be proposed from the crushing process, physical strengthening and chemical strengthening of RCA. The results have important scientific significance for revealing the adhesion characteristics and failure mechanism of RCA and natural aggregate/asphalt, and have significant practical value for promoting the large-scale utilization of HMA-RCA.

因具有特殊的表面构造与化学组成，再生集料(RCA)/沥青粘附规律极为复杂，使得HMA-RCA（含再生集料的沥青混合料）的路用性能随RCA掺量的变化规律不可预测，潜在早期损害风险，给规模化再利用带来了障碍。本项目以微纳观测试技术和宏观试验为主要手段，量化评价RCA化学组成与表面微观构造（SMM），明确各化学组成对表面能参数、集料/沥青粘附功的影响排序，揭示RCA/沥青粘附的化学作用微观机制；探明集料/沥青宏观粘附强度的影响因素及其权重，建立SMM与粘附强度的精细化模型，揭示RCA/沥青粘附的物理作用微观机制；揭示由SMM衰减、水分与沥青老化引起的RCA/沥青粘附失效机理，从RCA的破碎、物理强化与化学强化等方面推荐技术经济最佳的增强措施。成果对揭示RCA(也包括天然集料)/沥青粘附的化学与物理作用微观机制及其失效机理有重要的理论意义，对促进HMA-RCA规模化利用具有显著意义。

再生集料（RCA）因具有特殊的表面构造与化学组成，导致其与沥青粘附规律极为复杂，使得HMA-RCA（含再生集料的沥青混合料）的路用性能随RCA掺量的变化规律不可预测。潜在的早期损害风险给规模化再利用带来了障碍。然而，受测试技术的限制，现有的粘附理论所需要的微观参数无法直接测定或量化评价，使得有效性无法验证，更无法深层次揭示集料表面微观构造与化学组成对粘附性的影响机制，由此所提出的改善措施针对性不强，由粘附性不足所导致的路面水损害并没有得到很好解决。本项目基于XRF与CLSM微观测试，量化评价了集料化学组成与表面微观构造，揭示了不同于天然集料的RCA化学组成与表面微（纳）观构造特性；基于AFM与Pull-off试验，明确了不同化学组成对表面能参数与集料/沥青粘附功的影响排序，建立了RCA表面微观构造与RCA/沥青粘附强度的精细化模型，揭示了不同于天然集料的RCA/沥青粘附的化学与物理作用微观机制；研究了RCA表面微观构造衰减（或变化）、水分与沥青老化对RCA/沥青粘附的影响规律，揭示了RCA/沥青粘附失效机理；从RCA物理强化与化学强化等方面，推荐了技术经济效益最佳的RCA/沥青粘附增强措施，大幅提升HMA-RCA的路用性能。研究成果对揭示RCA（也包括天然集料）/沥青粘附的化学与物理作用微观机制及其失效机理有重要的理论意义，对促进HMA-RCA规模化利用具有显著意义。