Abstract: In order to promote the development of green and low-carbon recycling technologies for waste materials in road construction, typical hard sandstone from Southwest China was taken as base layer aggregate. The high-temperature rutting resistance and low-temperature cracking resistance tests were conducted by adding RAP obtained from a highway surface layer. A study on the proportioning of recycled sandstone ATB-25 was conducted based on the balanced design method. The results show that the optimum asphalt-aggregate ratios for recycled sandstone ATB-25 with RAP contents of 0%, 10%, 20%, 30%, 40%, and 50% were 3.8%, 4.0%, 4.2%, 4.4%, 4.5%, and 4.6%, respectively. When the RAP content is increased from 0% to 20%, the dynamic stability of the sandstone ATB-25 is increased from 1 875 times/mm to 2 417 times/mm, with an approximate improvement of 28.9%. However, when the RAP content is continued to increase from 20% to 50%, the dynamic stability is gradually decreased to 1 917 times/mm. Meanwhile, to ensure the water stability of the recycled sandstone ATB-25, the immersion Marshall test and freeze-thaw splitting test was compared. It is revealed that by incorporating 2.30% of ordinary Portland cement by total aggregate mass as an anti-stripping agent to replace a portion of mineral powder, the water stability of recycled sandstone ATB-25 with RAP contents from 0% to 50% can be effectively ensured. Finally, through dynamic modulus tests at different temperatures and loading frequencies, the master curves of the dynamic modulus for recycled sandstone ATB-25 were established using the Sigmoidal function and Williams-Landel-Ferry (WLF) equation. When the RAP proportion was 0%, 10%, 20%, 30%, 40%, and 50%, the corresponding dynamic moduli of recycled sandstone ATB-25 were 5 835, 7 103, 6 086, 5 749, 5 624, and 5 651 MPa, respectively. In summary, the results indicate that recycled sandstone ATB-25 with RAP contents from 10% to 20% exhibits satisfactory pavement performance.

Key words: highway engineering; sandstone; asphalt stabilized macadam; reclaimed asphalt pavement (RAP); balanced design method; dynamic modulus master curve

摘要： 为促进绿色低碳筑路固废材料资源化利用技术的发展，以西南地区典型硬质砂岩作为基层集料，通过掺入某高速面层沥青回收旧料进行高温抗车辙与低温抗开裂试验，基于平衡设计法开展了再生砂岩ATB-25的配比研究。结果显示，旧料掺量分别为0%、 10%、 20%、 30%、 40%、 50%相应再生砂岩ATB-25的最佳油石比依次为3.8%、 4.0%、 4.2%、 4.4%、 4.5%、 4.6%。其中，当旧料掺量从0%增大至20%时，ATB-25动稳定度由1 875次/mm增大至2 417 次/mm，提升约28.9%，但随着旧料掺量从20%继续增大至50%，动稳定度逐渐降低至1 917次/mm。同时，为了确保再生砂岩ATB-25的水稳定性，通过浸水马歇尔和冻融劈裂试验对比发现，掺入占集料总质量2.30%的普通硅酸盐水泥作为抗剥落剂替代部分矿粉，能有效保障0%~50%旧料掺量下再生砂岩ATB-25的水稳定性。最后，通过不同温度与加载频率下动态模量试验，运用Sigmoidal函数和WLF方程建立了再生砂岩ATB-25的动态模量主曲线，旧料掺量为0%、 10%、 20%、 30%、 40%、 50%相应再生砂岩ATB-25动态模量分别为5 835、 7 103、 6 086、 5 749、 5 624、 5 651 MPa。综上表明，旧料掺量为10%~20%的再生砂岩ATB-25具有较好的路用性能。

关键词: 道路工程； 砂岩； 沥青稳定碎石； 回收旧料； 平衡设计法； 动态模量主曲线