Characteristics of Alkali-activated Natural Hwangtoh Paste Utilizing Microwave Heating

In this study, the potential use of indigenous natural loess(Hwangtoh) as a new construction material, via alkali activation in conjunction with microwave heating, was investigated. Hwangtoh pastes with three different mix proportions of varying alkali liquid concentrations at a constant liquid-to-Hwangtoh ratio of 0.55 were prepared. Through the investigation it was found that it is possible to prepare Hwangtoh paste with 19.02 N/㎟ at tile age of 4 hours with the alkali solution of 8M NaOH and 1:4.5 mass ratio of liquefied Na₂SiO₃ at the curing temperature of 60℃ by microwave heating. The strength development at early age of tile alkali activated Hwangtoh paste specimens may be attributed to both a higher rate of reaction and moisture evaporation due to microwave heating.