Effect of dehydration time and air tightness on pore distribution of potassium and metakaolin-based geopolymer

As a catalyst support in the nuclear waste containers in the Fukushima Daiichi Nuclear Power Station, geopolymer is required to show high strength, high porosity and durability. The aim of this study is to evaluate the mechanical properties and pore size distribution of hardened samples based on two test variables, which include early-age dehydration time and air tightness. The early-age dehydration time ranges from 1-4 d, and air tightness is implemented using the two methods of total sealing and air contact. However, the average pore size was around 2.0 × 10² μm, the Vickers hardness was around 90 MPa, and the relative weight change on the 14th day was within 10% for all the samples that were not affected by the curing time and air tightness. It can be inferred that the pores of the sample may have been formed within a day and may not be affected by the curing time. (author)