Effect of Air Entrainment on Cemented Mine Backfill Properties: Analysis Based on Response Surface Methodology

Hefni, Mohammed A.; Hassani, Ferri

doi:10.3390/min11010081

Cited by 10 publications

(4 citation statements)

References 45 publications

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“…After removing each hardened sample from the cylindrical mold by injecting air pressure into the predrilled hole at the bottom of the mold [75] and finishing both surfaces using a surface grinder equipment to achieve a flat area, the height and diameter of samples were measured carefully in terms of maintaining a height-to-diameter ratio within 2 to 2.5 according to ASTM D2166 [76]. All of that comes before conducting the UCS test, which was successfully performed by Unitronic Compression (model S205-05M) made by MATEST Co., Italy, which has a load capacity of up to 50 kN (Figure 5).…”

Section: Uniaxial Compressive Strength (Ucs) Testmentioning

confidence: 99%

Eco-Sustainable Recycling of Cement Kiln Dust (CKD) and Copper Tailings (CT) in the Cemented Paste Backfill

2023

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Cement global demand shows continued growth and a significant increase in the production volume, which may negatively impact the non-renewable natural resources and the environment, which is incompatible with sustainability goals. Cement kiln dust (CKD) is a primary concern associated with clinker manufacturing as a waste byproduct. Similarly, the mining industry produces copper tailing as unwanted material while beneficiating the ore, creating environmental problems due to difficulty in managing worldwide generated quantities that reach billions of metric tons. This study investigated the beneficial utilization of cement kiln dust and copper tailing as undesirable wastes in industrial applications through underground mines’ cemented paste backfill (CPB). Sixty different mixtures were prepared with three types of CKD collected from various cement manufacturers and were accordingly used with a proportion of 5, 10, and 15% to partially replace ordinary Portland cement (OPC) and pozzolan Portland cement (PPC) binders, represented in hundreds of CPB samples. The hardened specimens were subjected to density, uniaxial compressive strength (UCS), and axial deformation measurements to evaluate the physical and mechanical properties at curing up to 90 days. Meanwhile, X-ray powder diffraction (XRD) was extensively applied to chemically investigate the hydration products of CPB-hardened mixtures. Moreover, we developed a UCS predictive model applying two techniques: multiple variables regression analysis and artificial neural network (ANN). The results showed that the tricalcium silicate (Alite) and dicalcium silicate (Belite) phases form C-S-H upon hydrations and provide high strength in the binary mixtures. Meanwhile, the CKD’s lime saturation factor (LSF) governed the strength value in the ternary mixtures that utilized copper tailings. That makes CKD practical in the CPB mixture when partially replacing the OPC and PPC binders, with a proportion of up to 15%. In addition, the ANN technique’s predictive model exhibited a significant positive correlation with excellent statistical parameters that achieved 0.995, 0.065, and 0.911 for R2, RMSE, and MAE, respectively.

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Section: Uniaxial Compressive Strength (Ucs) Testmentioning

confidence: 99%

Eco-Sustainable Recycling of Cement Kiln Dust (CKD) and Copper Tailings (CT) in the Cemented Paste Backfill

2023

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“…Several works (e.g. Dai et al, 2019;Sun et al, 2020;Hefni and Hassani, 2021) have been done on CPB materials through the RSM technique. Nevertheless, none of them mentions the effect of silicate modulus, slag fineness and activator concentration on 3-and 28 day UCS of AAS-CPB.…”

Section: Introductionmentioning

confidence: 99%

Strength Analysis and Optimization of Alkali Activated Slag Backfills Through Response Surface Methodology

Dai

Ren

et al. 2022

Front. Mater.

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The significant difference in water-to-binder ratio, activator type and concentration between alkali-activated slag (AAS) paste/mortar/concrete and AAS-based cemented paste backfill (AAS-CPB) means that previous results related to the properties and mix optimization of AAS materials cannot be directly translated to AAS-CPB. This study statistically identifies the effect of key influential variables such as silicate modulus, slag fineness and activator concentration on 3- and 28 day unconfined compressive strength (UCS) of AAS-CPB by central composite design (CCD) established in response surface methodology (RSM). In this study, the prominence of independent variables and their relations are investigated by using ANOVA (analysis of variance) having a significant level of 0.05. ANOVA results certify that there is a strong link between the level of variable contribution on UCS performance of AAS-CPB and curing age. Obviously, silicate modulus and activator concentration are the most major variables influencing UCS at 3 and 28 days, respectively. Increased fineness of slag and higher pH of pore solution enhance 3 day UCS, but restrain the further hydration of unreacted slag and subsequent the gain in strength at advanced curing ages. The combination of independent variables of silicate modulus (0.295), slag fineness (12630.2), activator concentration (0.45) gives the optimum responses.

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“…The development system applied in mineral extraction was analyzed, and a method of selecting deposit development technology and reasonable filling mixture composition under given filling parameters was proposed. Saudi Arabian scholars [22,23] studied the effects of cement and air-entraining doses on the strength, fresh density, and dry density of mine backfilling materials through a uniaxial compressive strength test. The research results showed that the air-entraining admixture can effectively improve the strength of the backfilling material and improve its filling fluidity.…”

Section: Introductionmentioning

confidence: 99%

Evolution Characteristics of Overlying Strata Fractures in Paste Composite Filling Stope

Guo

Wang

et al. 2022

Minerals

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Paste composite filling mining (PCFM) is one of the effective ways to achieve water-preserved mining (preservation of the waterproof strata). To investigate the laws of fracture propagation of the overlying strata in the PCFM stope, a kinematic model of overlying strata in the PCFM was established, which identified the major determinants to the development of overlying strata fractures. Taking the 112,201 working face of the test mine as the research background, the physical similar simulation, numerical computation, and theoretical analysis were combined to analyze the development characteristics of overlying strata fractures in the PCFM under the reaction between many factors (mining height, filling ratio, burial depth). The results show that the larger the mining height of the working face, the larger the development degree of overlying strata fractures. When the mining height is smaller, fractures are mostly distributed on both sides of the coal wall; when the mining height is larger, overlying strata fractures are mostly distributed on both sides of the coal wall and the upper part of overlying strata. The larger the paste filling ratio of the working face, the smaller the development degree of overlying strata fractures. Overlying strata fractures are mostly distributed in overlying strata on both sides of the coal wall. When the filling ratio of the working face increases, it is possible to effectively control the development of overlying strata fractures. The shallower the burial depth of the working face is, the faster the fractures are developed. With the increase of the burial depth, the development of overlying strata fractures is reduced, and overlying strata fractures will finally tend to be a stable value. The research results provide an important theoretical foundation for the application of the localized paste filling mining technique in the water-preserved mining, and also complement the theories of filling mining.

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Effect of Air Entrainment on Cemented Mine Backfill Properties: Analysis Based on Response Surface Methodology

Cited by 10 publications

References 45 publications

Eco-Sustainable Recycling of Cement Kiln Dust (CKD) and Copper Tailings (CT) in the Cemented Paste Backfill

Eco-Sustainable Recycling of Cement Kiln Dust (CKD) and Copper Tailings (CT) in the Cemented Paste Backfill

Strength Analysis and Optimization of Alkali Activated Slag Backfills Through Response Surface Methodology

Evolution Characteristics of Overlying Strata Fractures in Paste Composite Filling Stope

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