Effect of Physical and Chemical Properties of Coal Gangue Under Different Geological Conditions on Mechanical Properties of Concrete

This paper investigated the influence of physical and chemical properties of coal gangue under different geological conditions and aggregate replacement rate (0, 30%, 60%, 100%) on the compressive strength of coal gangue concrete (CGC). The X-ray diffraction (XRD) test, water absorption test, apparent density test, crushing index test of aggregates and the compressive strength test of concretes were conducted. The experimental results indicate that the mineral and chemical compositions of coal gangue in different geologies are quite different. The compressive strength is higher in the coal gangue with low water absorption, high apparent density, and low crushing index. The coal gangue with more SiO2 content is more suitable to produce concrete aggregate. With the increase of replacement ratio of coal gangue coarse aggregate, the compressive strength of CGC decreases obviously, while the effect of fine aggregate replacement on compressive strength is not overt. Additionally, the research results provide a reference for classifying and utilizing of coal gangue and improving the utilization rate of CGC.