Microstructure of geopolymer accounting for associated mechanical characteristics under various stress states

Autor: Yu-Hsiang Hsiao, Tai-Tien Wang, Ta-Wui Cheng, Tzuu-Hsing Ueng, Syuan-Jhih Lyu
Rok vydání: 2013
Předmět:
Zdroj: Cement and Concrete Research. 54:199-207
ISSN: 0008-8846
DOI: 10.1016/j.cemconres.2013.09.007
Popis: Geopolymer was prepared with various SiO2/Na2O mole ratios and mechanical tests and microstructural analyses are performed to investigate how the constituents affect its mechanical behavior in distinct stress states. Laboratory results reveal that the SiO2/Na2O ratio affects the polymerization by influencing the formation of silicon Q4(mAl) structures. The proportion of Q4(4Al) correlates positively with the mechanical characteristics of geopolymer, and the proportion of Q4(2Al) correlates negatively with the mechanical characteristics of geopolymer. The proportions of Q4(mAl) affect the stress–strain curve and the failure modes of geopolymer under various confining pressures. Three types of stress–strain curves with different peak strengths and plastic deformations are obtained. Incomplete polymerization generates a geopolymer with an imperfect microstructure, which determines the plastic deformation while unloading. Polymerization of a geopolymer affects its apparent cohesion and friction angle. However, the friction-induced strength declines drastically when the failure mode changes from the split mode to the shear mode.
Databáze: OpenAIRE