煤气化渣对水泥混凝土性能的影响

Influence of Coal Gasification Slag on Cement Concrete Performance

为探讨煤气化渣应用于水泥混凝土的可行性,将2种类型的煤气化渣分别制备混凝土试件并对其性能进行研究。采用扫描电镜和能谱仪分析煤气化渣微观结构与元素组成,并测试其基本物理性能;进一步研磨煤气化渣,制备掺煤气化渣混凝土试件,测试混凝土的抗压强度、干缩性能,并与普通混凝土性能进行比较。结果表明:煤气化渣组分中含有大量非晶态胶凝活性物质,在混凝土中掺入研磨后的粗渣,其抗压强度远高于基准混凝土,且随着龄期延长后期强度持续上升;掺细渣混凝土强度低于基准混凝土,且细渣研磨后对强度增长不大;掺煤气化渣有利于减小混凝土干缩率,煤气化渣研磨后比表面积增大,混凝土干缩率略有增大;综合考虑,推荐在混凝土中使用研磨后的粗渣部分替代天然砂作为混凝土细集料。

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.