YU Rui (1986-), male, Ph.D., Professor. E-mail: r.yu@whut.edu.cn
There are two inherent drawbacks in designing ultra-high performance concrete (UHPC) by the modified Andreasen-Andersen (MAA) model, i.e., unproven reliability under wet conditions and ignorance of disturbing effect of steel fiber on particle packing skeleton. In this work, the D-optimal mixture design model and the equivalent spherical diameter of steel fires were adopted to verify and optimize the MAA model, and the properties of the optimized UHPC were utilized to verify the feasibility of the new proposed method. The results reveal that the MAA model is also suitable to be utilized under wet conditions. Moreover, the equivalent spherical diameter of steel fibers (L=13 mm, d=0.2 mm) is 5.65 mm, which is determined by evaluating the effect of screening particles and steel fibers on wet packing density. In addition, the employed steel fibers that are treated as spheroidal particles can be implanted into the MAA model for the optimized design of new UHPC, which has a densely packing structure and an admirable compressive strength.
| 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 |