In the present study, the valorization potential of marble waste in the presence of metakaolin via alkali activation was explored. The activating solution used consisted of NaOH and sodium silicate solutions. The effects of marble waste to metakaolin ratio, particle size of raw materials, curing temperature, and Na₂O/SiO₂ and H₂O/Na₂O molar ratios present in the activating solution on the main properties and the morphology of the produced alkali-activated materials (AAMs) was evaluated. The durability and structural integrity of the AAMs after firing at temperatures between 200 and 600 °C, immersion in deionized water and 1 mol/L NaCl solution for different time periods and subjection to freeze–thaw cycles were also investigated. Characterization techniques including Fourier transform infrared spectroscopy, X-ray diffraction, mercury intrusion porosimetry and scanning electron microscopy were used in order to study the structure of the produced AAMs. Τhe highest compressive strength (~36 MPa) was achieved by the AAMs prepared with marble waste to metakaolin mass ratio of 0.3 after curing at 40 °C. The results indicated that the utilization of marble waste in the presence of metakaolin enables the production of AAMs with good physical (porosity, density and water absorption) and mechanical properties, thus contributing to the valorization of this waste type and the reduction of the environmental footprint of the marble industry.

中文翻译：

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通过碱活化进行大理石废料的估价

在本研究中，探讨了通过碱活化在偏高岭土存在下大理石废料的增值潜力。所用的活化溶液由NaOH和硅酸钠溶液组成。大理石废料对偏高岭土的比例，原料的粒径，固化温度以及Na ₂ O / SiO ₂和H ₂ O / Na _2的影响评价了在活化溶液中存在的O摩尔比对所制备的碱活化材料（AAM）的主要性质和形态的影响。还研究了AAM在200至600°C之间的温度下燃烧，浸入去离子水和1 mol / L NaCl溶液中不同时间段以及经受冻融循环后的耐久性和结构完整性。为了研究所生产的AAM的结构，使用了傅里叶变换红外光谱，X射线衍射，压汞法和扫描电子显微镜等表征技术。在40°C固化后，用大理石废料与偏高岭土的质量比为0.3的AAM可获得最高的抗压强度（约36 MPa）。