Yang Qiang, Yin Huiming, He Xin, Chen Fangliang, Ali Ayman, Mehta Yusuf, Yan Beizhan
Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 USA.
Department of Civil Engineering and Engineering Mechanics, Columbia University, 610 Sleeley W. Mudd 500 West 120th Street, New York, NY, 10027 USA.
Transp Res D Transp Environ. 2020 Aug;85. doi: 10.1016/j.trd.2020.102415. Epub 2020 Jun 20.
To investigate the environmental impacts of reclaimed asphalt pavement (RAP) while it was freshly processed (i.e. hot mixed asphalt or HMA) and after being subjected to weathering, three RAP materials, namely north-RAP, central-RAP, south-RAP, from three plants and one fresh HMA loose mix samples (Fresh-HMA) throughout New Jersey, USA underwent four different weathering processes including: UV and precipitation weathering on unbounded RAP, UV and precipitation weathering on compacted RAP, weathering by heat and moisture cycles, and groundwater flow-through leaching. Batch experiments were conducted to mimic releasing of trace elements in weak acidic leachate from landfills. North-RAP and central-RAP released levels of Pb greater than the United States Environmental Protection Agency (USEPA) primary drinking water maximum contaminant level (MCL) of 15 μg/L. Novel two-column experiments (a RAP column followed by a soil column) were conducted to investigate the release of trace elements from RAP and the attenuation effect of soil on potential pollutants. The results of these experiments showed that pollutants released from RAPs such as Mn and Ni were largely attenuated in the soil. The results suggest that RAP can be used as an unbound material in environments except those acidic (i.e., pH < 5 as in mines with sulfur-containing minerals and landfills with acidic environment).
为了研究再生沥青路面（RAP）在刚加工时（即热拌沥青或HMA）以及经受风化后的环境影响，取自美国新泽西州三个工厂的三种RAP材料，即北RAP、中RAP、南RAP，以及一个新鲜的HMA松散混合料样本（新鲜HMA），经历了四种不同的风化过程，包括：无约束RAP的紫外线和降水风化、压实RAP的紫外线和降水风化、热和水分循环风化以及地下水渗滤浸出。进行了批量实验以模拟垃圾填埋场弱酸性渗滤液中微量元素的释放。北RAP和中RAP释放的铅含量高于美国环境保护局（USEPA）的主要饮用水最大污染物水平（MCL）15μg/L。进行了新型双柱实验（一个RAP柱后接一个土壤柱），以研究RAP中微量元素的释放以及土壤对潜在污染物的衰减作用。这些实验结果表明，从RAP中释放的污染物如锰和镍在土壤中大部分被衰减。结果表明，除了酸性环境（即pH<5的含硫矿物矿山和酸性环境的垃圾填埋场）外，RAP可作为无约束材料用于环境中。
