YIN B, JIA X L, HUANG P P,et al.Experimental study on the mechanical properties of fly ash paste filling material synergistically enhanced  by high-power ultrasound and alkali activation[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(2):64-75.

doi:10.16186/j.cnki.1673-9787.2024100026

Received:2025/07/20

Revised:2025/10/25

Published:2026/01/28

Experimental study on the mechanical properties of fly ash paste filling material synergistically enhanced  by high-power ultrasound and alkali activation

Yin Bo1,2, Jia Xiaolei1, Huang Pingping2, Lian Quandong3, Zhou Nan4, Li Xianfeng5, Wu Xiang6, Yang Ruizhou7, Yang Xiaoyan8

1.School of Resource and Environmental Engineering， Inner Mongolia University of Technology， Hohhot  010051， Inner Mongolia， China；2.Inner Mongolia Key Laboratory of Radar Technology and Application， Hohhot  010051， Inner Mongolia， China；3.Ordos Guoyuan Mining Development Co.， Ltd.， Ordos  010300， Inner Mongolia， China；4.School of Mines， China University of Mining and Technology， Xuzhou  221116， Jiangsu， China；5.Xinwen Mining Group Co.， Ltd.， Taian  271200， Shandong， China；6.Energy Technology Center of Inner Mongolia Autonomous Region， Hohhot  010098， Inner Mongolia， China；7.Inner Mongolia Coal Mine Design and Research Institute Co.， Ltd.， Hohhot  010020， Inner Mongolia， China；8.Inner Mongolia Institute of Metrology and Testing， Hohhot  010030， Inner Mongolia， China

Abstract: Objectives To address the problem of low early strength of fly ash paste filling material， this study investigates the mechanism and effectiveness of synergistic modification using high-power ultrasound and alkali activation.  Methods Single-factor experiments were conducted to analyze the effects of ultrasound time， ultrasound power， Na₂SiO₃ concentration， and NaOH concentration on the 1 d， 3 d， and 7 d peak strengths of fly ash paste filling material. Based on a three-factor， five-level central composite design （CCD） within the response surface methodology， the synergistic modification parameters of ultrasound and alkali activation were optimized. Furthermore， the microstructural changes after modification and the synergistic modification mechanism were systematically investigated.  Results The results indicate that the peak strength of fly ash paste filling material first increases and then decreases with increasing ultrasound time， ultrasound power， Na₂SiO₃ concentration， and NaOH concentration. The degree of influence of the four factors on peak strength follows the order： Na₂SiO₃ concentration; ultrasound time; ultrasound power; NaOH concentration. The optimal experimental conditions for the synergistic modification were an ultrasound time of 28.62 min， an ultrasound power of 700 W， and a Na₂SiO₃ concentration of 0.57 mol·L-1. The synergistic action of high-power ultrasound and alkali activation significantly enhanced the peak strength of the fly ash paste filling material， in which alkali activation played a dominant role， while high-power ultrasound exerted a strengthening effect.  Conclusions The synergistic effect of high-power ultrasound and alkali activation further accelerates the hydration reaction rate of fly ash paste filling material， increases the formation of hydration products， reduces material porosity， and consequently improves its mechanical properties.

Key words: fly ash paste filling material; high-power ultrasound; alkali activation; synergistic effect