矸石粒径及含量影响高砂高泡水泥基固结体强度机理研究

Mechanism study on influence of particle size and content of gangue on strength of high-sand and high-foam cement-based filling material

为研究矸石粒径及掺量对高砂高泡水泥基充填材料固结体(简称“基体”)强度的影响,通过宏观力学试验和微观结构观测,系统分析了3种密度等级(800,1000,1200 kg/m^3)基体的混合固结体强度变化规律,并结合其破坏特征,明确了矸石对基体强度的影响机理。结果表明:1)矸石粒径通过界面结构强度影响混合固结体强度,其强度随矸石粒径增大而减小,级配良好的连续级矸石(2~15 mm)混合固结体强度最大;2)矸石掺量对混合固结体的影响取决于矸石与基体的强度关系,矸石强度相对较大时,有利于混合固结体强度的提高,且混合固结体强度与矸石掺量呈正相关,Ⅲ类固结体相对于无矸固结体,强度最大增幅为29.8%,反之,矸石会降低固结体的强度,混合固结体强度最大降幅达到25%。研究结果可为高砂高泡水泥基材料充填设计提供参考。

In order to study effects of particle size and content of gangue on strength of high sand high foam cement-based filling material(for short,matrix),strength variation of mixed consolidation of matrix with three density grades(800,1000,1200 kg/m^3)were systematically analyzed through using macroscopic mechanical tests and microstructure observations.Meanwhile,combined with its damage characteristics,effect mechanism of gangue on matrix strength was clarified.Results show that:1)particle size of gangue affects strength of mixed consolidation body through strength of interface structure.Its strength decreases with the increase in particle size of gangue.The strength of mixed consolidation body of continuous grade gangue(2~15 mm)with good gradation is the greatest.2)Influence of gangue content on mixed consolidation body depends on strength relationship between gangue and matrix.When strength of gangue is relatively large,it is beneficial to increase strength of mixed consolidation body and mixed consolidation.Strength of consolidation is positively correlated with gangue content.Increase in maximum strength of type Ⅲ consolidation is 29.8%compared with that of non-gangue consolidation.On the contrary,gangue reduces the strength of consolidation,and the maximum strength decrease of mixed consolidation is 25%.Research results could provide reference for filling design of high sand and high foam cement-based materials.