Permeability and Microscopic Mechanism of Low Calcium Fly Ash Modified by Bentonite
SU Hang
XU Dongzhe
BA Hezuer
CUI Suli
Abstract：This study focuses on fly ash with free calcium oxide less than 10％as the main research object,and prepares mod-ified fly ash samples with bentonite content of 0％,4％,8％,12％,16％,20％,and 24％.By conducting combined tests of liquid limit and plastic limit,compaction test,permeability test,laser particle size analysis,X-ray fluorescence spectrometry analy-sis,and scanning electron microscope analysis on modified fly ash samples with different bentonite contents,the study summa-rizes the changes in physical properties of the modified fly ash samples with increasing bentonite content,the changes in per-meability coefficient with the effects of bentonite content,compaction degree,and flow time,and discusses the influence mechanism of bentonite modification on fly ash from the perspectives of particle distribution,mineral composition,and micro-structure.The results show that the addition of bentonite makes the modified fly ash have plasticity.With the increase in the content of bentonite,the maximum dry density of the modified fly ash increases linearly,and the optimum water content decreases as a quadratic function.The permeability coefficient of the modified fly ash decreases with the increase of bentonite content,and the reduction is more obvious with the increase of compaction degree.When the content of bentonite is greater than 20％,the permeability coefficient can be reduced to less than 10-7 cm/s.The permeability coefficient is affected by the flow time,and it changes gradually from decreasing to increasing and then stabilizing,or from decreasing to stabilizing.With the increase of bentonite content,the clay content in the improved fly ash increases,the effective particle size decreases,and new minerals such as phosphorite,sillimanite,sepiolite and hard zeolite are formed,thus improving the cementation ability of some particles of the improved fly ash and making the soil structure dense.Moreover,the addition of bentonite can effectively make up for the characteristics of large permeability and strong fluidity of fly ash,and can be applied to the engineering use of anti-seepage lining materials in special environments.
Keywords：improved fly ashBentonite contentpermeabilitymicroscopic mechanis
Publication Date：2025-06-30
Online Publishing Date：2025-09-22(First online date of this platform, not the publication date of the document)
Pages：9( 1-9 )