Abstract

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Author(s):: LIU Kai-ping; ZHAO Hong-yan; LI Zu-zhong; GUAN Yu; TANG Zhuo-qun; CHEN Qian; School of Materials Science and Engineering, Chang’an University

Keywords:: cement concrete; coal gasification slag; compressive strength; dry shrinkage rate

Abstract:: In order to investigate the feasibility of coal gasification slag used in cement concrete, two types of coal gasification slags were prepared separately for concrete specimens and their performances were studied. The microstructure and element composition of slags were analyzed by scanning electron microscopy and energy dispersive spectroscopy, and their basic physical properties were tested. The coal gasification slags were further milled and then prepared for concrete specimens, the compressive strength and dry shrinkage performance were tested and compared with those of common concrete. The results show that the coal gasification slags contain lots of amorphous cement active materials. The compressive strength of concrete with milled coarse slag is much higher than that of the reference concrete, and its later strength increases as the curing time extending. The compressive strength of concrete with milled fine slag is lower than that of reference concrete and its strength isn’t improved obviously for milled fine slag. The coal gasification slag is helpful to reduce the shrinkage of concrete, but the specific surface area of coal gasification slag increases after milling and leads to the dry shrinkage rate of concrete rising slightly. In consideration of the above results, it is recommended to replace the natural sand as the fine aggregate in concrete by using the milled coarse slag.