LI Ning (1970-), male, Senior Engineer. E-mail: lining-tlm@petrochina.com.cn
The influence of adding crystalline silica and silica fume on the mineral composition and physical-mechanical properties of the set-cement was investigated. The results show that optimizing the particle size distribution of cement dry blend can improve the 7-d compressive strength. Increasing the total silica addition can enhance the 30-d compressive strength. At 30-d curing, two optimized systems have an average compressive strength of greater than 40 MPa and a water permeability of lower than 2×10-6 μm2. The physical, mechanical, mineral and microstructual property evolution of the two systems within 30 d were analyzed. It is indicated that there are little changes in the mineral compositions and their crystallinity during 7-30 d. However, apparent microstructure coarsening occurs, leading to the decline in compressive strength and modulus of elasticity as well as the almost linear increase in water permeability of the set cement as a function of time.
| 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 |