Zhang Juhui (1981-), female, Ph.D., Associate Professor. E-mail: zhjhui@usst.edu.cn
Until now, many studies have been carried out to investigate the effect of reinforcement corrosion on concrete cracking due to chloride attack, but they mainly focus on monolithic reinforced concrete structures, and few studies on the durability of new and old concrete structures. Eight integral casting and secondary casting concrete specimens with different water-cement ratios (i.e., 0.60 and 0.53) were fabricated, and the semi-immersion accelerated corrosion was examined. The development law of rust expansion cracks on the concrete surface and the changes in the mechanical properties of the rusted steel bars for the secondary-casting specimens were investigated and compared with the integral-casting specimens at different theoretical corrosion rates of steel bars of 4%, 6% and 8%, respectively. The results show that the integrally poured concrete specimens only produce longitudinal cracks along the reinforcement, while the secondary-casting concrete specimens firstly produce interfacial transverse cracks and then produces longitudinal cracks. The steel bar in the integral-casting specimen is uniformly corroded, while the steel bars in the secondary pouring specimens are non-uniformly corroded, and the steel corrosion at the interface between unused and used concrete occurs most serious. The mechanical properties of the steel bars are reduced in the secondary-pouring specimens compared to the integral-pouring specimens due to the serious loss of the steel bar section at the interface between unused and used concrete. The influence of concrete strength on the mechanical properties of steel bars in the integral-casting specimens can be ignored, but it has an influence on the mechanical properties of steel bars in the secondary-casting specimens.
| 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 |