煤矸石是成煤过程中与煤层伴生的一种碳含量较低，但硬度和强度都高于煤的岩石，其大量堆积对煤矿周围的环境造成巨大危害。目前较优的煤矸石资源化利用方式是将其用于制作煤矸石混凝土 (Coal gangue concrete, CGC) 。然而在以往的实际应用研究中，CGC存在韧性差、易开裂以及抗拉能力弱以及煤矸石骨料易碎裂等缺点。这毫无疑问缩小了CGC在材料性能方面的应用范围。相关研究表明，在混凝土中掺加一定量的玄武岩纤维 (Basalt fiber, BF) ，能够有效的改善混凝土的宏微观性能。本文针对目前CGC性能上的不足，运用BF对CGC进行改性研究。从宏观力学性能、细观界面结构以及微观结构三个尺度下，探究BF对CGC的性能的影响，揭示了BF对CGC的力学性能的影响机理，并探讨了相应的细观和微观结构与宏观力学性能的关系。研究成果对CGC的应用推广具有重要意义。

本课题基于试验研究与理论分析相结合。以不同体积掺量 (0.1 vol%、0.12 vol%、0.15 vol%以及0.18 vol%) 、不同长度 (6 mm, 18 mm, 30mm) 的BF掺入到CGC中，分别从宏观、细观、微观三个尺度下，分别对其工作性能、力学性能、界面过渡区结构、孔结构和微观形貌进行研究，揭示了影响玄武岩纤维-煤矸石混凝土 (Basalt fiber coal gangue concrete, BFCGC) 的工作性能和力学性能的细微观机理。本研究的主要结论如下：

(1) 运用BF对CGC进行改性处理时，其新拌CGC的流动性受BF的影响较大，且掺入的BF掺量越大，长度越长，新拌混凝土工作性能越差。然而，再掺入适量的粉煤灰能够弥补这一问题带来的不足。

(2) 宏观尺度研究结果表明：首先，BF对CGC的力学性能的改善效果具有双重效应。适量的BF的参与能够改善CGC的力学性能，但掺量过多时会产生团聚效应，使得CGC容易发生应力集中，损害混凝土的强度，建议最优掺量为0.15 vol %。其次，掺入较长的纤维能够在一定程度上改善CGC的力学性能，30 mm长的纤维效果最优；最后，在选择最优的BF掺量和长度的分组同时掺入适量的粉煤灰后能进一步提高其混凝土的强度。30 % 的粉煤灰与 0.15 vol %的BF共同组合掺入CGC中，对其力学性能的改善效果最好。

(3) 细观尺度的研究结果表明：在CGC中掺入BF ，需要考虑BF对其ITZ结构的影响。BF的掺入能够有效的缩减ITZ的最薄弱区域，同时提高最薄弱区域的显微硬度值，进而达到增强CGC的ITZ强度的目的。同时掺入适量的粉煤灰也能提高混凝土ITZ的显微硬度，改善BFCGC的ITZ结构。

(4) 微观尺度的研究表明：首先，掺入BF使得CGC的总孔隙率增加，然而适当的掺量和长度的纤维掺入后能后分化大孔，增加凝胶孔的孔径，优化CGC的孔径结构；其次，BF在CGC中通过物理和化学的方法与水泥基材结合，从而发挥拉结锚固的效果，增强了CGC的抗拉强度和ITZ的强度。最后，适量的BF能够在CGC中形成三维的网状骨架，既能起到均匀的传递应力的作用，又能使CGC的内部结构变得密实，减少CGC内部由于煤矸石的掺入而形成的水化缺陷。然而，过量的BF在CGC中会产生“抱团”效应，致使混凝土内部产生缺陷，导致应力集中的发生。同时，适量的粉煤灰的二次水化反应有助于BF的粘结和混凝土强度的提升。最后，基于灰色关联度理论，探究了不同类型的孔隙对BFCGC的抗压强度的影响，并通过建立GM (1，2)模型，更好的预测BFCGC的抗压强度随孔结构的变化规律。

Coal gangue is a kind of rock associated with coal seam in the process of coal formation. Its carbon content is low, but its hardness and strength are higher than that of coal. It accumulates in large quantities around the coal mine, causing great harm to the environment. It accumulates in large quantities in the surrounding environment of coal mine and causes great harm. At present, the better resource utilization method of coal gangue is to use it to make coal gangue concrete (CGC). This undoubtedly reduces the application scope of Coal gangue Concrete in material performance. In this paper, aiming at the shortcomings of CGC performance, basalt fiber (BF) is used to modify CGC. The effect of BF on CGC performance was explored from three scales of macroscopic mechanical properties, meso-interface structure and microstructure, and the influence mechanism of BF on CGC mechanical properties was revealed, and the relationship between corresponding meso-structure and macroscopic mechanical properties was also discussed. The research results are of great significance to the application and promotion of CGC.

This subject is based on the combination of experimental research and theoretical analysis. BF with different volume contents (0.1 vol%, 0.12 vol%, 0.15 vol% and 0.18 vol%) and different lengths (6 mm, 18 mm and 30 mm) were added into CGC. The working properties, mechanical properties, interface transition zone structure, pore structure and micro morphology of BFCGC were studied from macro, micro and micro scales, respectively, and the micro and micro mechanisms affecting the working properties and mechanical properties of BFCGC were revealed. The main conclusions of this study are as follows:

(1) Adding BF into CGC has a great influence on the slump of fresh concrete. The greater the amount of fiber added and the longer the length, the worse the working performance of fresh concrete. After mixing fly ash and BF, it can effectively increase the slump of concrete and improve the working performance of freshly mixed BFCGC.

(2) Macro scale research results show that: Firstly, BF has a dual effect on the improvement of the mechanical properties of CGC. The participation of an appropriate amount of BF can improve the mechanical properties of CGC, but when the amount is too much, it will produce agglomeration effect, which makes CGC prone to stress concentration and damage the strength of concrete. It is suggested that the optimal dosage is 0.15 vol%. Secondly, adding longer fibers can improve the mechanical properties of CGC to a certain extent, and the best effect is 30 mm long fibers; Finally, the strength of concrete can be further improved by adding an appropriate amount of fly ash in the optimal BF dosage group at the same time. When 30% fly ash and 0.15 vol% BF are combined into CGC, the effect of improving its mechanical properties is the best.

(3) The results of meso scale research show that: When BF is added into CGC, the effect of BF on its ITZ structure needs to be considered. The incorporation of BF can effectively reduce the weakest area of ITZ and improve the microhardness of the weakest area, so as to enhance the ITZ strength of CGC. At the same time, an appropriate amount of fly ash can also improve the microhardness of concrete ITZ and improve the ITZ structure of BFCGC.

(4) Micro scale research shows that: First, the total porosity of CGC increases with the incorporation of BF. However, after proper incorporation and length of fiber incorporation, the macropores can be differentiated, the pore size of the gel pores increases, and the pore structure of CGC is optimized. Secondly, BF is combined with cement substrate through physical and chemical methods in CGC, so as to play the effect of tension and anchorage, and enhance the tensile strength of CGC and the strength of ITZ. Finally, an appropriate amount of BF is conducive to the improvement of the internal structure of concrete, while excessive BF is easy to increase the internal defects of concrete, reduce the compactness and reduce the bonding performance. At the same time, the secondary hydration reaction of an appropriate amount of fly ash is conducive to the bonding of BF and the improvement of concrete strength. Finally, based on the grey correlation theory, the influence of different types of pores on the compressive strength of BFCGC is explored, and the GM (1,2) model is established to better predict the variation law of the compressive strength of bfcgc with the pore structure.

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