CO2-mineralized pretreatment of high-calcium fly ash and its effect on mechanical properties of geopolymers
XIONG Xufeng
YANG Guangzhao
HUANG Furen
WU Yingzhe
ZHONG Kaihong
Abstract：To improve the hydration activity and volume stability of high-calcium fly ash(HCFA)in concrete,geopolymers were prepared using three types of high calcium fly ash as a single precursor,subjected to intact state and CO2 mineralization pre-treatment for 6 and 24 hours,respectively,and the influence of mineralization degree on the physicochemical properties of HCFA was investigated,and its mechanism of action was analyzed.The results showed that with the increasing degree of mineralization,the free calcium oxide content in the samples decreased by 2.64 percent point and 2.80 percent point,and the 1-day compressive strength of the geopolymer prepared from HCFA pretreated with 6 h of CO2 mineralization could reach 29.7 MPa,which was im-proved by 34.4％.This was because the 6 h of carbonation pretreatment for HCFA could promote the generation of hydration prod-ucts and nucleation and crystallization.However,if the carbonation pretreatment time was long(24 h),it was detrimental to the strength development of the HCFA-based geopolymer.
Keywords：high-calcium fly ashcarbonationfree calcium oxidegeopolymercompressive strength
Publication Date：2024-11-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 39-42 )