Abstract
In order to study the static and dynamic mechanical characteristics of the coal gangue concrete used in the mine support structure, the compressive strength test, the drop weight impact test, and the Split Hopkinson Pressure Bar (SHPB) test were conducted. The compressive strength, initial and final impacting energy, dynamic strength, and failure characteristic of concrete were obtained of the concrete single‐doped with coal gangue coarse aggregate, single‐doped with coal gangue fine aggregate, and codoped with coal gangue coarse and fine aggregates. The results show that (1) it is feasible that employing coal gangue to replace natural coarse and fine aggregates in concrete can prepare C30 and C40 concrete; (2) the addition of coal gangue fine aggregate has a positive effect on the impact energy of the initial and final cracks of concrete, while the addition of coal gangue coarse aggregate has a negative effect on it; (3) compared with the static strength, the dynamic strength of concrete is improved no matter whether coal gangue is added to concrete; (4) the incorporation of coal gangue coarse aggregate will make the concrete shear surface smooth; (5) at the given impacting pressure, the concrete with coal gangue coarse aggregate has greater particle breakage and those with coal gangue fine aggregate has less. The research of this study can be a reference for the application of gangue concrete in mine support structures.
Highlights
In recent years, the concept of sustainable development and ecological environmental protection has become deeply rooted in the hearts of people, and various countries have begun to attach importance to the protection of the natural environment and ecological balance [1,2,3]
Comparing the dynamic compressive strength under 0.4, 0.5, 0.6, and 0.7 MPa gas pressure with the static compressive strength, under the design strength of C30, the ordinary concrete increased by 11.2%, 16.5%, 25.1%, and 31.3%, respectively; the concrete single-doped with coal gangue fine aggregate increased by 9.8%, 17.0%, 23.0%, and 30.4%, respectively; the concrete single-doped with coal gangue coarse aggregate increased by 10.6%, 13.5%, 22.2%, and 28.1%, respectively; and the concrete codoped with coal gangue coarse and fine aggregates increased by 9.1%, 14.7%, 21.4%, and 30.4%, respectively
Under the design strength of C40, the ordinary concrete increased by 13.5%, 21.3%, 25.5%, and 32.2%, respectively; the concrete single-doped with coal gangue fine aggregate increased by 8.3%, 13.7%, 20.5%, and 30.1%, respectively; the concrete single-doped with coal gangue coarse aggregate increased by 13.2%, 17.2%, 20.8%, and 25.8%, respectively; and the concrete codoped with coal gangue coarse and fine aggregates increased by 11.0%, 18.0%, 22.3%, and 26.1%, respectively
Summary
The concept of sustainable development and ecological environmental protection has become deeply rooted in the hearts of people, and various countries have begun to attach importance to the protection of the natural environment and ecological balance [1,2,3]. For supporting engineering of concrete with coal gangue corroded by acid solution, a series of concrete tests were conducted by Li et al [3] and concluded that, in premise of low concrete strength requirements (less than 10 MPa), it is completely feasible to use coal gangue to replace the concrete coarse aggregate in acid solution. E experimental results demonstrate that the addition of an appropriate alkali activator can improve the compressive strength of coal gangue concrete. There is no relevant studies on the dynamic properties of concrete with coal gangue, which limits the promotion and application of coal gangue concrete. Based on the above analysis, for supporting a coal mine supporting engineering in Huainan, China, the static and dynamic mechanical properties of coal gangue concrete were studied. The compressive strength, initial and final impacting energy, dynamic strength, and failure characteristic of concrete were obtained of single-doping coal gangue coarse aggregate, single-doping coal gangue fine aggregate, and codoping coal gangue coarse and fine aggregates. e obtained results may be used for supporting the coal mine engineering
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