Effect on the performance of shotcrete mixed with silica fume and fly ash
- ZHANG Luchen, LI Shuchen, LI Shucai, LIAO Qikai
JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2016, 46(5):
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To solve the problems of shotcrete in the field, such as the low strength, much cracking, high rebound and dust concentration, adding different mass ratio of silica fume and fly ash to replace the cement in the shotcrete, the influence of silica fume and fly ash on the performance of shotcrete with aluminate liquid accelerator was studied through laboratory and field tests. The results showed that the coagulation effect was the best when the dosage of aluminate liquid accelerator was 3% of cementing material. A silica fume dosage of 8% could effectively promote the coagulation effect of aluminate liquid accelerator, and improve the strength and the cohesiveness of concrete. The addition of fly ash could reduce the coagulation effect of accelerator, reduce the strength and improve the workability of concrete. The addition of silica fume, fly ash and aluminate liquid accelerator affected the 1d compressive strength of concrete, and the order of influence factors was fly ash content>accelerator dosage>silica fume content. The order of influence factors for 28 d compressive strength of concrete was accelerator dosage>silica fume content>fly ash content. Based on the above analyses, the optimal proportion was obtained. Combined with a new spraying technology in-situ, the best combination could effectively reduce cement amount, improve shotcrete strength, reduce cracking, and lower rebound and dust.