摘要
针对超远距离输送过程中,特殊管路布置等充填技术中堵管、爆管风险大,管道磨损严重等问题,采用改性镁渣(MMS)和粉煤灰(FA)在不同配比下制备超高流动性新型膏体充填材料(UH-MFPB),探究其早期强度、流动性以及流变特性,并建立流动性和流变参数的相关关系.研究结果表明:(1)UH-MFPB样品的单轴抗压强度随FA含量增加呈先增大后减小的趋势.当FA质量分数为20%时,样品的抗压强度最大,养护28 d可达到6.759 MPa,后期强度持续增加;(2)新鲜UH-MFPB料浆的坍落度为25.6~29.2 cm,扩展度为61~93.1 cm,具有很好的流动性;(3)新鲜UH-MFPB料浆的流变特性符合Herschel-Bulkley模型,流变参数(屈服应力、塑性黏度和触变性)随FA含量的增大而减小,且FA质量分数达到20%时,料浆出现剪切增稠的现象;(4)新鲜UH-MFPB料浆的流动性和流变参数满足二次多项式关系,呈现出负相关性.
With its continuous application and promotion,filling technology,such as an ultra-long distance and special pipeline arrangement,faces an increasing demand,and the demand for the fluidity of filling material is also rising.Aiming at the large risk of blocking pipes and tubes in filling technology,the serious wear of pipelines,etc.,and using modified magnesium slag(MMS)and fly ash(FA)to prepare high liquidity under different ratios of a new type of paste filling material(UH-MFPB),this paper probes this material’s early strength,liquidity,and rheological properties,and establishes the relationship between liquidity and rheological parameters.First,MMS and FA samples were prepared at different ratios of certain concentrations and cured for 3,7,28,and 56 days to measure their uniaxial compressive strength.The uniaxial compressive strength of a UH-MFPB sample increases first and then decreases with increasing FA content,and gradually increases with curing age.When FA content is 20%,the compressive strength of the sample reaches the maximum.At 3,7,28,and 56 days,the intensity was 1.335,2.161,6.759,and 12.104 MPa,respectively.Then,the slump and spread of fresh UH-MFPB slurry were measured.They increased with FA content,with a slump of 25.6–29.2 cm and a spread of 61–93.1 cm,showing good fluidity.Then,the rheological properties of fresh UH-MFPB slurry were measured in accordance with the Herschel–Bulkley model,and the relationship between shear stress and plastic viscosity and the shear rate was discussed,as well as the effect of FA content on rheological parameters and mechanisms.The shear stress is found to increase with the shear rate,and the viscosity decreases exponentially and then slowly with increasing shear rate.Rheological parameters(yield stress,plastic viscosity,and thixotropy) decrease with increasing FA content, and the slurry undergoes shear thickening when FA content reaches 20%. The Crossviscosity model was used to fit the viscosity curve of fresh slurry. Finally, the correlation between the fluidity and rheological parametersof fresh UH-MFPB slurry was discussed, and the yield stress was found to correlate negatively with the slump, plastic viscosity, andexpansion, which were quadratic polynomials. Considering all factors, when FA content is between 10% and 30%, UH-MFPB slurry hasultra-high fluidity and high strength, which can play a good role in filling slurry transport.
作者
刘浪
谢磊
朱梦博
阮仕山
孙伟吉
邵成成
LIU Lang;XIE Lei;ZHU Meng-bo;RUAN Shi-shan;SUN Wei-ji;SHAO Cheng-cheng(Energy School,Xi’an University of Science and Technology,Xi’an 710054,China;Mine Functional Backfill Technology Research Center,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《工程科学学报》
EI
CSCD
北大核心
2023年第8期1324-1334,共11页
Chinese Journal of Engineering
基金
国家自然科学基金资助项目(52074212,51674188)
陕西省自然科学基础研究计划资助项目(2015JQ5187)
陕西省教育厅科研项目(15JK1466,19JK0543)。
关键词
改性镁渣
抗压强度
超高流动性
流变性
长距离输送
modified magnesium slag
compressive strength
ultra-high liquidity
rheology
long-distance delivery