The effect and mechanism of alkali activator on the properties of geopolymers
ZHANG Maoliang
MA Yan
LI Jianwei
WANG Jinhua
WAN Xindi
Abstract：A metakaolin fly ash based geopolymer was prepared using metakaolin and fly ash as cementitious materials,and sodium silicate and NaOH as alkali activators.Orthogonal experimental design was used to study the effects of modulus,water-solid ratio,and solid content of sodium silicate on its mechanical properties and dry density.The mechanism of alkali activators was analyzed and explored by SEM,XRD and other microscopic methods.The results show that the influencing factors of the 28 d compressive strength of geopolymer from large to small are water-solid ratio,sodium silicate modulus and solid content,and the optimal parameters of alkali activator are water glass modulus 1.0,water-solid ratio 0.48 and solid content 36%,at this time,the 28 d compressive strength of geopolymer reaches 33.5 MPa and the dry density is 1.6 g/cm3.XRD analysis show that there is a"steamed bread peak"in geopolymer at 15°～40°,forming a cementitious structure with amorphous structure.
Keywords：alkali activatormetakaolinfly ashgeopolymers
Publication Date：2025-12-25
Online Publishing Date：2026-01-13(First online date of this platform, not the publication date of the document)
Pages：4( 25-27,83 )