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Experimental study on mechanical properties and microstructure of powdered coal gangue concrete |
LI Wen1, WANG Hailong1*, ZHANG Jiahao2, YANG Hong3, FENG Shuai4 |
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, Inner Monglia 010018, China |
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Abstract In order to explore the influence of rubber powder content on the mechanical properties of coal gangue coarse aggregate concrete, 20 mesh rubber particle content(0, 3%, 6%, 9%, 12%)of rubber powder coal gangue concrete was designed, and the macroscopic mechanical test and the microscopic pore structure nuclear magnetic resonance test were carried out.The results show that the increase of powder content is negatively correlated with the mechanical strength, and the effect of 3% powder content is the least, which is 1.3% lower than that of the reference group. Fitting the conversion formula of cubic compressive strength and splitting tensile strength of 20 mesh gangue concrete with different powder content has a good correlation. The addition of rubber powder reduces the proportion of harmful pores, and the content of 6% rubber powder reduces the distribution of harmful pores in gangue concrete by 4%. The data show that the rubber powder particles can fill the pores, reduce the occurrence of damage pores and optimize the pore structure. A GM(1,3)model is established by selecting the most influential factors on the strength: bound fluid saturation(correlation degree 0.951 06)and pore radius ratio greater than 0.02 μm(correlation degree 0.963 86).The average error predicted by the model is 2.56%. It provides a reference basis for the green concrete which can be used locally for the slope protection material of mine dump.
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Received: 04 November 2021
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