Cenospheres are low-density and hollow microspheres derived from coal-fired power plant fly ash waste. This study aims to prepare ultra-light-weight (<1000 kg/m3 wet density) concrete using fly ash cenospheres (FAC). To begin with, FAC's shell thickness and the water absorption and desorption were characterized. A mixing procedure was designed to avoid the segregation between the FAC and cement slurry. FAC can affect the rheological properties of fresh mixture over time through absorption and desorption of free water. The presented ultra-light-weight concrete has several advantages compared to the ones prepared using foaming methods. First, shrinkage is significantly reduced due to FAC's internal restraint and curing effects. Secondly, it has good mechanical performance, especially in bending and is more environmentally friendly due to use of less cement. X-ray computed tomography illustrates that FAC ultra-light-weight concrete has smaller pores of more uniform size compared with those prepared using foaming methods. X-Ray diffraction, thermal gravimetry-derivative thermal gravimetry, fourier-transform infrared spectroscopy and scanning electron microscopy are employed for the hydration products and microstructure characterization. Outcomes prove that FAC can combine well with the cement matrix, and react with calcium hydroxide to produce C-A-S-H through pozzolanic reaction.

中文翻译：

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粉煤灰球超轻量混凝土的流变学、收缩率、力学性能和微观结构


Cenospheres 是源自燃煤发电厂粉煤灰废物的低密度空心微球。本研究旨在使用粉煤灰 cenospheres （FAC） 制备超轻 （<1000 kg/m3 湿密度） 混凝土。首先，对 FAC 的壳厚度和吸水解吸进行了表征。设计了一种混合程序来避免 FAC 和水泥浆之间的离析。FAC 可以通过吸收和解吸游离水来随着时间的推移影响新鲜混合物的流变特性。与使用发泡方法制备的混凝土相比，所提出的超轻混凝土具有几个优点。首先，由于 FAC 的内部约束和固化效果，收缩率显著降低。其次，它具有良好的机械性能，尤其是在弯曲方面，并且由于使用较少的水泥而更加环保。X 射线计算机断层扫描表明，与使用发泡方法制备的混凝土相比，FAC 超轻混凝土具有更小的孔隙和更均匀的尺寸。X 射线衍射、热重导数热重、傅里叶变换红外光谱和扫描电子显微镜用于水合产物和微观结构表征。结果表明，FAC 能与水泥基体很好地结合，并与氢氧化钙反应，通过火山灰反应生成 C-A-S-H。