A key question concerning the application of recycled concrete aggregates (RCA) into pavement is the assessment of self-cementing properties of RCA, which increase the strength and stiffness of unbound base and subbase layers. In this paper, the assessment of self-cementing properties of RCA, the hydration of unhydrated binder and their influence on the microstructure and mechanical behaviour were studied by subjecting two different RCA (NRCA and ORCA, showing significantly different self-cementing properties), after curing for 0, 360 and 720 days, to the thermogravimetric analysis (TGA), scanning electron microscopic analysis (SEM) and monotonic triaxial tests. The results show that the unhydrated binder content of NRCA is low (between 6.2% and 7.9% in fines), and most of the unhydrated binder was hydrated after curing for 360 days. Besides, the sulfate attack products, ettringite, were also observed from both TGA and SEM, which could also lead to the self-cementing properties. The hydration products of unhydrated cement and sulfate attack products not only form bonds between particles, but also fill the small pores (width less than 3 μm), turning the open type of an unbound structure to a rigid dense skeleton structure.

将再生混凝土骨料（RCA）应用于路面的一个关键问题是评估 RCA 的自胶结性能，该性能可提高未粘合基层和底基层的强度和刚度。本文通过两种不同的RCA（NRCA和ORCA，显示出显着不同的自胶结性能），研究了RCA的自胶结性能的评估、未水化粘结剂的水化及其对微观结构和力学行为的影响，固化0、360和720天，进行热重分析（TGA）、扫描电镜分析（SEM）和单调三轴测试。结果表明，NRCA的未水化粘结剂含量较低（细粉中为6.2％至7.9％），并且大部分未水化粘结剂在固化360天后发生水化。此外，从 TGA 和 SEM 中还观察到了硫酸盐侵蚀产物钙矾石，这也可能导致自胶结性能。未水化水泥的水化产物和硫酸盐侵蚀产物不仅在颗粒之间形成键合，而且填充了细小的孔隙（宽度小于3μm），将非键合结构的开放型转变为刚性致密的骨架结构。