| Summary: | 碩士 === 國立臺北科技大學 === 資源工程研究所 === 107 === In this study, Using ground granulated blast furnace slag (GGBFs) combined with calcium hydroxide and gypsum products to prepar a new type of alkali-activated binder. The reaction of aluminum ions with sulfate ions in the presence of calcium ions in aqueous solution to form ettringite supplemented by pozzolanic reaction leading to the formation of calcium silicate and calcium aluminosilicate hydrates. In the experiment, the physical properties, volume stability and microscopic characteristics of the binder were investigated with different gypsum product fineness, water-to-binder ratio, gypsum product type, gypsum product addition ratio and GGBFs percentage.
When the water-to-binder ratio is 0.4, the ratio of calcium hydroxide to gypsum product is 4, the compressive strength of the binder can reach 44 MPa at 28 days. The compressive strength and setting time were compliance with the specifications of blast-furnace cement in Taiwan and Japan. Thermogravimetric mass loss showed that the hydrated product increased in the temperature range of 40~200℃ with the age, indicating that the amount of hydrated product increased as the increase of age. When the ratio of calcium hydroxide to gypsum product was changed to 0.43, result in gypsum product was added, and more ettringite was formed, but the results showed of XRD and SEM analysis still lot of gypsum were remained that make the strength of the binder was reduced. XRD analysis of different gypsum product binder for 28 days showed that the building gypsum has more significant reactivity than the other in the alkali-activated binder material.
Despite the expansion and shrinkage rate of the binder was prepared by building gypsum is stable at normal temperature, but the appearance of the sample after drying at a temperature of 105℃ has more cracks obviously as the amount of building gypsum increases. The dry shrinkage indicates that the gypsum product still needs to consider the volume stability caused by the drying of the sample when added to the alkali-activated binder material. However, the binder after high temperature and high pressure curing in Autoclave still maintains a complete type, and the autoclave test expansion and shrinkage rate were compliance with the specifications of blast-furnace cement in Taiwan and Japan.
|
|---|
