Development and Characteristics of Aerated Alkali-Activated Slag Cement Mixed with Zinc Powder

Experiments on the development and properties of aerated concrete based on alkali-activated slag cement (AASC) and using Zn powder (ZP) as a gas agent were carried out. The experiments were designed for water-binding material (w/b) ratios of 0.35 and 0.45, curing temperatures of 23 ± 2 °C and 40 ± 2 °C, and ZP of 0.25%, 0.50%, 0.75%, and 1.0%. ZP generates hydrogen (H₂) gas in AASC to form pores. At a w/b of 0.35, the curing temperature had little effect on the pore size by ZP. However, a w/b of 0.45 showed a clear correlation that the pore diameter increased as the curing temperature increased. The low w/b of 0.35 showed a small change in the pore size according to the curing temperature due to the faster setting time than 0.45 and the increased viscosity of the paste. Therefore, at a termination time exceeding at least 60 min and a w/b of 0.45 or more, it was possible to increase the size and expansion force of the pores formed by the ZP through the change of the curing temperature. ZP showed applicability to the manufacture of AASC-based aerated concrete, and the characteristics of foaming according to the curing temperature, w/b ratio, and ZP concentration were confirmed.