Full
WANG Jingyu (1994-), male, Master candidate. E-mail: wangjy123123@163.com
Outline
The effects of borax, sodium gluconate and L(+)-tartaric acid on the hardening behavior and strength development of rapid-hardening calcium sulphoaluminate cement mixed with calcium chloride solution at -10 ℃ were investigated. The results show that the initial and final setting time of rapid-hardening calcium sulphoaluminate cement mixed with calcium chloride solution prolonge to 25 min and 28 min with 0.6% borax at -10 ℃, respectively. However, the setting time of pastes with sodium gluconate or L(+)-tartaric acid does not extremely change. The strength gradually decreases in the samples with increasing the dosages of borax and sodium gluconate at different ages. A maximum reduction of 25.5 MPa occurs in those samples. The strength of samples containing L(+)-tartaric acid sharply decreases. A reduction of 10.9 MPa in 3-day samples containing 0.3% tartaric acid and 27.3 MPa in 28-day samples containing 0.6% tartaric acid occur. The presence of 0.6% borax does not change the morphology of ettringite at 1 d, but decreases the amount of ettringite by 5.31%. A short column-like ettringite in the samples with sodium gluconate and a needle-shaped-like ettringite in the samples with L(+)-tartaric acid are detected, respectively. However, the amount of ettringite in those two samples above has no remarkable change. Borax is a suitable retarder for calcium sulphoaluminate cement at -10 ℃ because of the feasibility of setting prolongation and the acceptable strength reduction. Sodium gluconate and L(+)-tartaric acid have a slight effect on the setting time but change the ettringite morphology and deteriorate the strength.
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| 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 |
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