LIU Zhiyong(1985-), male, Ph.D., Professor. E-mail: liuzhiyong0728@163.com
The damage of ultra-high performance concrete (UHPC) under load-temperature coupling was evaluated by using the indexes of ultrasonic pulse velocity, mass loss rate, bulk density and thermal conductivity. The results show that the ultrasonic pulse velocity (UPV) of UHPC decreases, and the damage increases gradually with the increase of load. The temperature has little effect on the UHPC damage and the UPV fluctuates at 4.55 km/s. The bulk density decreases slightly with the increase of load and temperature, i.e., only 0.73% and 1.80%, respectively, at a stress ratio of 0.5 and a temperature of 90℃. The test results of mass loss rate show the similar regularity. Load and temperature both have a greater influence on the thermal conductivity of UHPC. The thermal conductivity decreases with the increase of the increase of load and temperature. At 3 d, the thermal conductivity of UHPC in the presence of a stress ratio of 0.5 is decreased by 21.80%, compared to that in the absence of load, and the thermal conductivity of UHPC at 90℃ is decreased by 14.90%, compared to that at 30℃. A meso model of thermal conductivity of the UHPC under load-temperature coupling was proposed based on the assumption that the thermal conductivity of solid phase in UHPC could increase linearly with increasing saturation and eliminate the effects of load and temperature on the UHPC porosity. It is indicated that the theoretical values calculated by the model could be in reasonable agreement with the measured data.
| 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 |