【摘要】 针对全取代煤矸石粗骨料混凝土力学性能差的问题，本研究通过硅灰改性的方式，采用宏观力学性能试验，探究硅灰对全煤矸石粗骨料混凝土立方体抗压强度、劈裂抗拉强度的影响规律。采用回归分析方法，建立劈裂抗拉强度与抗压强度的经验换算方程，同时结合核磁共振技术和扫描电子显微镜技术，从微观角度阐述硅灰对全煤矸石粗骨料混凝土力学性能的影响机理。结果表明，硅灰可以改善全煤矸石粗骨料混凝土的抗压强度和劈裂抗拉强度，掺量在10%附近，混凝土力学性能最优，建立的强度换算方程具有一定的实用性；硅灰主要细化了混凝土的有害孔和多害孔，提升了全煤矸石粗骨料混凝土的强度，不同孔隙半径的积分面积与全煤矸石粗骨料混凝土抗压强度的定量关系主要为线性关系，有害孔为指数关系；硅灰掺入全煤矸石粗骨料混凝土后水化产物结构更加稳定，消耗了界面过渡区范围内的Ca（OH）₂,生成的三维C-S-H凝胶和钙矾石作为骨架结构桥连了煤矸石粗骨料与砂浆基体，细化并减少了混凝土内部孔隙与微裂缝是混凝土强度提高的主要原因。低掺量的硅灰将全煤矸石粗骨料混凝土强度等级提升后完全可以用于当地的大中修工程。更多还原

【Abstract】 In view of the poor mechanical properties of full coal gangue coarse aggregate concrete, through the macroscopic mechanical property test of silica fume modification, this study explores the effect of silica fume on the cube compressive strength and splitting tensile strength of all coal gangue concrete. By using the method of regression analysis, the empirical conversion equation of splitting tensile strength and compressive strength is established, combined with nuclear magnetic resonance technology and scanning electron microscope technology, the effect mechanism of silica fume on the mechanical properties of full coal gangue coarse aggregate concrete is expounded from the microscopic point of view. The test results show that silica fume can improve the compressive strength and splitting tensile strength of full coal gangue coarse aggregate concrete, and the mechanical properties of concrete are the best when the content is about 10%. The strength conversion equation is practical. Silica fume mainly refines the harmful holes and multi-harmful holes of concrete, and improves the strength of full coal gangue coarse aggregate concrete. The quantitative relationship between the integral area of different pore radius and the compressive strength of coal gangue concrete is mainly linear, and the harmful hole is exponential. The hydration product structure of silica fume mixed with coal gangue concrete is more stable, which consumes Ca（OH）₂ in the interface transition zone. The resulting three-dimensional C-S-H gel and ettringite as a skeleton structure bridge the coarse aggregate of coal gangue and mortar matrix, refine and reduce the internal pores and micro-cracks of concrete, which is the main reason for the improvement of concrete strength. After the strength grade of all coal gangue concrete is raised by low content of silica fume, it can be used in local large and medium repair projects.更多还原