ZHANG Ai (1992-), female, Doctoral candidate. E-mail: zgaino1@163.com
1H low-field nuclear magnetic resonance instrument was used to continuously monitor the changes in the transverse relaxation time of white cement with silica nanoparticles with different sizes (i.e., 15 nm, 50 nm and 100 nm) from adding water to hydration for 72 h. The effect of silica nanoparticles with different sizes on the hydration process of cement was investigated. The setting time of cement paste was measured using the Vicat apparatus. The results show that the crystal nucleation of silica nanoparticles can affect the early hydration process of cement, thus breaking the flocculation structure of cement paste due to the physical adsorption and pozzolanic reaction, reducing the number of macropores, and improving the uniformity of cement paste. In addition, the smaller the silica nano particles is, the less the free water content in hydration process and the shorter the setting time will be.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |