Fiore Nicola, Bruno Salvatore, Del Serrone Giulia, Iacobini Franco, Giorgi Gabriella, Rinaldi Alessandro, Moretti Laura, Duranti Gian Marco, Peluso Paolo, Vita Lorenzo, D'Andrea Antonio
Department of Civil, Constructional and Environmental Engineering, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy.
Technical Department, Rete Ferroviaria Italiana S.p.a., Piazza della Croce Rossa 1, 00161 Rome, Italy.
Materials (Basel). 2023 Feb 4;16(4):1335. doi: 10.3390/ma16041335.
Environmental safeguards promote innovative construction technologies for sustainable pavements. On these premises, this study investigated four hot mix asphalt (HMA) mixtures-i.e., A, B, C, and D-for the railway sub-ballast layer with 0%, 10%, 20%, and 30% reclaimed asphalt pavement (RAP) by total aggregate mass and a rejuvenator additive, varying the bitumen content between 3.5% and 5.0%. Both Marshall and gyratory compactor design methods have been performed, matching the stability, indirect tensile strength, and volumetric properties of each mixture. Dynamic stiffness and fatigue resistance tests provided mechanical performances. Laboratory results highlighted that the RAP and the rejuvenator additive increase the mechanical properties of the mixtures. In addition, the comparative analysis of production costs revealed up to 20% savings as the RAP content increased, and the life cycle impact analysis (LCIA) proved a reduction of the environmental impacts (up to 2% for resource use-fossils, up to 7% for climate change, and up to 13% for water use). The experimental results confirm that HMA containing RAP has mechanical performances higher than the reference mixture with only virgin raw materials. These findings could contribute to waste management and reduce the environmental and economic costs, since the use of RAP in the sub-ballast is not, so far, provided in the Italian specifications for railway construction.
环境保护措施推动了可持续路面创新施工技术的发展。在此前提下，本研究针对铁路底碴层，研究了四种热拌沥青（HMA）混合料，即A、B、C和D，其中再生沥青路面（RAP）占总集料质量的0%、10%、20%和30%，并添加了再生剂添加剂，沥青含量在3.5%至5.0%之间变化。采用了马歇尔试验和旋转压实机设计方法，以匹配每种混合料的稳定性、间接拉伸强度和体积特性。动态刚度和疲劳抗性试验提供了力学性能。实验室结果表明，RAP和再生剂添加剂提高了混合料的力学性能。此外，生产成本的对比分析显示，随着RAP含量的增加，成本节约高达20%，生命周期影响分析（LCIA）证明环境影响有所降低（资源使用——化石方面降低高达2%，气候变化方面降低高达7%，用水方面降低高达13%）。实验结果证实，含有RAP的HMA的力学性能高于仅使用原始原材料的参考混合料。这些发现有助于废物管理，并降低环境和经济成本，因为目前意大利铁路建设规范中并未规定在底碴中使用RAP。
