INFLUENCE OF ADMIXTURES ON CEMENTED BACKFILL STRENGTH

2002 ◽  
Vol 11 (03) ◽  
pp. 261-270 ◽  
Author(s):  
C. WANG ◽  
D. D. TANNANT ◽  
A. PADRUTT ◽  
D. MILLETTE
Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Huafu Qiu ◽  
Fushun Zhang ◽  
Lang Liu ◽  
Dongzhuang Hou ◽  
Bingbing Tu

Tailing cement filling is an important development direction in mine filling, as it is a green and environmentally friendly method for efficiently treating solid waste in mines. Adding a certain amount of waste rock can effectively improve the backfill strength and better meet the filling strength requirements. To address the use of waste rock tailings in cemented filling materials, a uniaxial compression test was carried out on backfills with different cement/sand ratios and waste rock contents, and the influence of the cement/sand ratio and waste rock content on the strength of the backfill was studied. This study found that when the waste rock content is certain, the strength of the backfill increases with the increase in the cement/sand ratio, and the increase in strength slows with the increase in the cement/sand ratio until the strength of the backfill reaches a limit and no longer increases. When the cement/sand ratio is constant, the strength of the backfill first increases and then decreases as the waste rock content increases. When the cement content is constant, the addition of a certain amount of waste rock reduces the specific surface area of the solid materials in the backfill, increases the amount of cement per unit area, and improves the strength of the backfill. When the waste rock content is too high, due to the large particle size of the waste rock, the tailings cannot completely wrap around the waste rock, resulting in a weakening of the cement in the backfill, which reduces the strength of the backfill. This study found that the waste rock content and the cement/sand ratio in the backfill have a significant impact on backfill damage. The damage is mainly caused by insufficient cement strength. The presence of waste rock will change the original direction of crack propagation, resulting in more crack bifurcation, and the form of the destruction surface on the backfill is complicated and diverse.


Author(s):  
Shuai Li ◽  
Yulin Zhang ◽  
Ru Feng ◽  
Haoxuan Yu ◽  
Jilong Pan ◽  
...  

As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement–sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50–100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.


2020 ◽  
Vol 1 ◽  
Author(s):  
Mohammed A. Hefni

Abstract The use of natural pozzolans in concrete applications is gaining more attention because of the associated environmental, economic, and technical benefits. In this study, reference cemented mine backfill samples were prepared using Portland cement, and experimental samples were prepared by partially replacing Portland cement with 10 or 20 wt.% fly ash as a byproduct (artificial) pozzolan or pumice as a natural pozzolan. Samples were cured for 7, 14, and 28 days to investigate uniaxial compressive strength development. Backfill samples containing 10 wt.% pumice had almost a similar compressive strength as reference samples. There is strong potential for pumice to be used in cemented backfill to minimize costs, improve backfill properties, and promote the sustainability of the mining industry.


2021 ◽  
Vol 280 ◽  
pp. 122408
Author(s):  
Nan Zhou ◽  
Erbao Du ◽  
Jixiong Zhang ◽  
Cunli Zhu ◽  
Huaqiang Zhou

2018 ◽  
Vol 37 (2) ◽  
pp. 691-705 ◽  
Author(s):  
Bing-qian Yan ◽  
Kouame-Joseph-Arthur Kouame ◽  
Dwayne Tannant ◽  
Wen-sheng Lv ◽  
Mei-feng Cai

2020 ◽  
Vol 399 ◽  
pp. 122993
Author(s):  
Shitong Zhou ◽  
Xibing Li ◽  
Yanan Zhou ◽  
Chendi Min ◽  
Ying Shi
Keyword(s):  

2021 ◽  
Vol 768 (1) ◽  
pp. 012100
Author(s):  
Hanbo Wei ◽  
Zhenjiang Wen ◽  
Lei Ba ◽  
Qian Gao

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