Experimental study on sand fixation characteristics of modified fly ash materials
LU Haifeng1，2，LI Zhongyang1，ZHANG Kai1
(1. School of Civil Engineering，Wuhan University，Wuhan，Hubei 430072，China；2. Hubei Key Laboratory of Geotechnical and Structural Engineering Safety，Wuhan University，Wuhan，Hubei 430072，China)
Abstract：Fly ash is a byproduct of thermal power generation that requires proper disposal. While it is abundant in western China，transportation and disposal costs can be significant. Furthermore，the regions of western Ningxia and Gansu are facing a severe desertification problem. This research aims to explore the potential of fly ash modified materials for sand fixation，while considering the balance between supply and demand. To develop reference and fixation standards based on the effect of sand fixation，the mechanical properties，hydration products，and microstructure of modified fly ash sand fixation materials were studied through various analytical methods，including uniaxial compressive strength test，water content test，scanning electron microscope test (SEM)，X-ray diffraction test(XRD)，and shear test. The results suggest a noteworthy enhancement in the uniaxial compressive strength and cementation effect of the modified fly ash materials. The hydrated calcium silicate gel formed after the hydration of the modified fly ash materials appears to be the key factor in explaining the difference in water retention. Additionally，the cohesive force of the 10% alkali exciter-modified fly ash cement increased to more than three times the original，and the shear strength of the 30% magnesium slag-modified fly ash cement was significantly improved. The article suggests considering the use of a low-dose alkali exciter，approximately 2.5%，or a high-dose magnesium slag modified fly ash，greater than 30%，while adjusting the ash-to-sand ratio accordingly to optimize both economic benefits and sand fixation effects.
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2024, Vol. 43 
