Bimodal pore size evolution of metakaolin-based geopolymers at the initial stage of curing; A Small-angle neutron scattering study

硬化初期におけるメタカオリン系ジオポリマーの二峰性細孔径変化; 中性子小角散乱による研究

戸田 賀奈子*; 元川 竜平   ; 斉藤 拓巳*

Toda, Kanako*; Motokawa, Ryuhei; Saito, Takumi*

The development of the nano-scale pore size distribution of metakaolin-based geopolymers (MKGPs) was evaluated by the application of the small-angle neutron scattering (SANS), followed by the polydisperse spherical (PDSP) model application, where the modelled outputs were then deconvoluted by bimodal log-normal distribution fitting. Small pores, with a log-normal distribution modal value of 2.5 nm, immediately formed after mixing, with a decrement in the pore volume as a function of time. Larger pore size distribution with log-normal distribution modal values larger than 4nm, required an induction period, indicating the larger pore size distribution evolution corresponds to the pores as aluminosilicate cluster gel interstices. The nano-scale pore size distribution development varied by the curing temperature and the type of activators, which were evaluated in this study. The initial pore evolution of the MKGPs may be the critical step in determining the nano-sized porosity of the MKGPs, which characterizes the diffusive property of the material, such as the De of HDO.