公路工程

为探究软质布敦岩沥青(Buton Rock Asphalt, BRA)作为沥青改性和再生双重功效添加剂的效果，以常用的中面层沥青混合料AC-20C为研究对象，基于响应面优化法设计室内试验，对不同软质BRA掺量(1%～5%)及不同沥青混合料回收料(Reclaimed Asphalt Pavement, RAP)掺量(10%～50%)的改性热再生混合料进行组配设计与性能检验，提出了软质BRA的最佳掺量；基于此，通过不同RAP掺量的软质BRA改性热再生混合料的路用性能验证，并与普通沥青混合料进行对比，确定了适宜的RAP掺量范围。研究结果表明：软质BRA中纯沥青的稠度及高、低温性能介于A-70~#基质沥青与硬质BRA纯沥青及RAP旧沥青之间，具有良好的黏弹性和较多的轻质组分，可作为再生剂使用；随着软质BRA和RAP掺量的增加，改性热再生混合料的总最佳油石比增大，而基质沥青最佳油石比减小，即软质BRA可替代部分基质沥青，推荐其最佳掺量为3%;与普通混合料相比，当RAP掺量不超过30%时，软质BRA的掺入能综合提高改性热再生混合料的高温稳定性、水稳定性、低温抗裂性能和抗渗性能，可作为改性剂使用，并建议RAP的适宜掺量为10%～30%。因此，软质BRA可作为一种新型经济环保的绿色改性再生剂用于沥青路面厂拌热再生工程。

To explore the effect of soft Buton Rock Asphalt(BRA) as a dual functional additive agent for asphalt modifying and rejuvenating, the commonly used asphalt mixture AC-20C of middle surface layer was taken as the research object. The indoor experiments were designed based on the response surface optimization method to carry out the mix design and performance tests for the modified hot recycled mixtures with different soft BRA contents(1%～5%) and different Reclaimed Asphalt Pavement(RAP) contents(10%～50%), and the optimal soft BRA content was proposed. Based on this, the pavement performances of soft BRA modified hot recycled mixtures with different RAP contents were verified, and compared with the common asphalt mixture to determine the suitable RAP content range. The results show that the consistency, high-and low-temperature performances of pure asphalt in soft BRA are between those of A-70# matrix asphalt and pure asphalt in hard BRA as well as RAP waste asphalt. The pure asphalt of soft BRA has good viscoelasticity and more light components, which can be used as rejuvenating agent. With the increase of soft BRA and RAP contents in the modified hot recycled mixtures, The overall optimal oil stone ratio of the modified hot recycled mixture increases, while the optimum oil-stone ratio of matrix asphalt decreases. That is, soft BRA can replace part of matrix asphalt, and its optimal content is recommended to be 3%. Compared with the common mixture, when the RAP content does not exceed 30%, the mixing of soft BRA can comprehensively improve the high-temperature stability, water stability, low-temperature crack resistance and impermeability of the modified hot recycled mixtures, which can be used as modifying agent. It is suggested that the suitable content of RAP is 10%～30%. Therefore, the soft BRA can be used as a new type of economical and environmentally friendly green modifying and rejuvenating agent for central plant hot-mix asphalt recycling projects.