ZHANG Qianqian (1986—), female, Master, Senior Engineer. E-mail: zhangqianqian@cnjsjk.cn
To improve the workability of ultra-high performance concrete (UHPC), the effect of superplasticizers (i.e., carboxylic-superplasticizer and phosphonic-superplasticsizer) on the rheological properties of cement/silica fume pastes with a low water-binder ratio was investigated, and the adsorption behavior of the superplasticizers in paste, the packing density and the viscosity of interstitial solution were analyzed. The results show that the superplasticizers have a preferential adsorption behavior on different particle surfaces, and carboxylic-superplasticizer has a superior adsorption ability on cement particle surfaces, and phosphonic-superplasticsizer has a stronger adsorption ability on silica fume particle surfaces. It is indicated that for a cement paste with the similar flow spread, a lower viscosity of the interstitial solutions is the main reason for a lower viscosity of paste with carboxylic-superplasticizer rather than that with phosphonic-superplasticsizer. However, the well- dispersion of silica fume particles with phosphonic-superplasticizer can result in an increased packing density, thus leading to a lower viscosity of cement-silica paste, compared to that of paste with carboxylic-superplasticizer.
| 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 |