抄録
Zeolitic tuff which was milled to different particle size was reacted with 50 mass% of ordinary portland cement as pozzolanic resource in the condition of 60°C-2h steam cure and 180°C-4h hydrothermal treatment. For comparison, fly ash was also used as pozzolanic resource. The structure and the humidity controlling performance of the hardened bodies were investigated. The product from zeolitic tuff of which mean particle size was 7 μm contained portlandite and amorphous calcium silicate hydrate. After hydrothermal treatment, almost all portlandite changed to C-S-H and tobermorite reacting mainly with mordenite in zeolitic tuff but crystalline foreign substances like feldspar. The main peak of pore diameter in the hardened body after hydrothermal reaction was about 4 nm irrelevant to the particle size of the pozzolanic resource. Water vapor adsorption isotherm of the product which was dried at 150°C showed rapid adsorptive and desorptive variation in the range of 30-50 RH%. Compared with the product from fly ash, the amount of water vapor adsorption in the product using zeolitic tuff showed 2 times as much. This result corresponds to the pore volume that was measured by N2 gas adsorption isotherms. By using bead mill, the mean particle size of zeolitic tuff could reach to 240 nm. The product made by this pozzolanic resource using steam cure and hydrothermal treatment showed that the pore volume around 4 nm considerably increased (0.62 cm3 g-1), and so did the amount of water vapor adsorption and desorption.
