The petrographic and mechanical heterogeneity of construction and demolition waste (CDW) strongly affects the physic-mechanical performance of new concrete and mortar mixes (RAC: recycled aggregate concrete and RAM: recycled aggregate mortar) made with these recycled aggregates (RA). It is thus extremely important to quickly discriminate and sort them in groups of materials with homogeneous petrography, similarly to primary natural raw materials. Eighteen CDW samples, divided in six groups (natural stones, concrete, bricks, perforated bricks, roof tiles and tiles), from the Abruzzo region (central Italy) are analysed by both micro-X-ray fluorescence energy-dispersive spectroscopy (XRF-EDS) and hyperspectral imaging (HSI), in particular in the short wavelength infrared range (SWIR). Every SWIR spectrum is characterized by three regions of absorption at the following wavelength ranges: 1330–1680 (I), 1830–2140 (II) and 2140–2400 nm (III), displaying the lowest, highest and intermediate intensities, respectively. The first and second wavelength regions are linked to O–H and H––H motions, whereas the highest wavelength range is linked to atoms bonded to the O–H environment and/or to the carbonate group. According to previous analysis and to the micro-XRF-EDS surface chemistry, the amount of CaCO is rich to very rich for concrete and natural stones, intermediate to absent for masonries and absent for tiles. The intensity or area (%) of the absorption component vibrating at about 2345 nm is directly proportional to the amount of CaO (CaCO and CO), and inversely to SiO and AlO. Therefore, SWIR can rapidly detect and separate CDW as a function of their carbonate to aluminosilicate contents, i.e. concrete and natural stones made with limestone masonries and tiles. The attained outcomes are of paramount importance either for routinely screening or in post-disaster circumstances.

中文翻译：

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通过近红外光谱表征 CDW 类型：实现再生骨料的自动选择

建筑和拆除废物（CDW）的岩相和机械异质性强烈影响用这些再生骨料（RA）制成的新型混凝土和砂浆混合物（RAC：再生骨料混凝土和RAM：再生骨料砂浆）的物理机械性能。因此，与初级天然原材料类似，快速区分和分类具有均匀岩相学的材料组非常重要。来自阿布鲁佐地区（意大利中部）的 18 个 CDW 样品分为六组（天然石材、混凝土、砖块、穿孔砖、屋顶瓦片和瓷砖），通过微 X 射线荧光能量色散光谱 (XRF- EDS）和高光谱成像（HSI），特别是在短波长红外范围（SWIR）。每个 SWIR 光谱都具有以下波长范围内的三个吸收区域：1330–1680 (I)、1830–2140 (II) 和 2140–2400 nm (III)，分别显示最低、最高和中间强度。第一和第二波长区域与 O-H 和 H--H 运动相关，而最高波长范围与与 O-H 环境和/或碳酸酯基团键合的原子相关。根据之前的分析和微 XRF-EDS 表面化学，混凝土和天然石材中 CaCO 的含量从丰富到非常丰富，砖石中 CaCO 的含量为中等到不存在，瓷砖中则不存在。在约 2345 nm 处振动的吸收成分的强度或面积 (%) 与 CaO (CaCO3 和 CO) 的量成正比，与 SiO2 和 Al2O3 成反比。因此，SWIR 可以根据碳酸盐与铝硅酸盐含量（即由石灰石砖石和瓷砖制成的混凝土和天然石材）快速检测和分离 CDW。无论是对于常规筛查还是在灾后情况下，所取得的成果都至关重要。