Document Details
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Document Type |
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Thesis |
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Document Title |
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Cement Kiln Dust (CKD) as a Co-Binder for Cemented Paste Backfill of Base Metal Underground Mines استخدام غبار افران الاسمنت كمادة اسمنتية مساعدة في خلطة الردم الاسمنتية بالمناجم العميقة لمعادن الأساس |
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Subject |
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Faculty of Engineering |
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Document Language |
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Arabic |
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Abstract |
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With the continuity in cement demand growth, global production is expected to be increased, which may cause environmental concerns incompatible with sustainability objectives. Cement kiln dust (CKD) is a significant waste material induced by cement production. Utilizing this by-product waste material in industrial applications is a global focus that many scholars are investigating in various fields. Similarly, copper tailing as unwanted material is produced in the mining industry while beneficiating the ore and creating environmental problems due to difficulty managing worldwide generated quantities that reach billions of metric tons. In the mining industry, cemented paste backfill (CPB) is a relatively new technology compared to backfill methods. However, the binder price significantly influences the cost of this method. This research aimed to beneficially investigate the utilization of cement kiln dust and copper tailing as undesirable wastes in industrial applications through underground mines' cemented paste backfill (CPB). Sixty-five binary and ternary mixtures were prepared over the experimental campaign, including a preliminary and comprehensive investigation phase. This study used four proportions of CKD (5, 10, 15, and 20%) to replace cement partially, represented in more than 950 samples prepared. Raw materials were characterized from physical and chemical perspectives. Meanwhile, the hardened samples were subjected to density, uniaxial compressive strength (UCS), and axial deformation tests to measure the physical and mechanical properties at curing times of 7, 14, 28, 56, and 90 days. And then calculating the elastic modulus from the UCS curves. In addition to applied X-ray fluorescence (XRF), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), and Energy-dispersive X-ray (EDX) techniques for analyzing the CPB-hardened mixtures chemically. And for linking the physical and mechanical behaviors of binary and ternary mixtures with the chemical content, which is one contribution of this study. The results showed that CKD increased the binary mixture strength by up to 30% for OPC and up to 15% for PPC compared to the control mixes. CKD could also be used beneficially in the CPB ternary mixture to replace the main binder (cement) with a proportion of up to 20%. At 28 days of curing, prepared mixtures meet the compressive strength requirement for CPB to achieve stability in underground mines. A noticeable inverse relationship was observed over the tested samples between the highest compressive strength achieved and CKD's lime saturation factor (LSF) at 90 days of curing time in the CPB ternary mixture. This study also applied multiple linear regression (MLR) and artificial neural network (ANN) with a multilayer perceptron feed-forward backpropagation training algorithm to develop the UCS predictive models. ANN 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, which introduces the ANN as an intelligent tool to perform optimized cemented paste backfill (CPB) operation. Calcium silicate hydrates (C-S-H), Portlandite, and Calcite achieved the most significant phases upon hydration in the predictive models, and PPC, OPC, YCKD, ACKD, and UCKD have the highest importance as mixtures components. |
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Supervisor |
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Dr. Haitham M. Ahmed |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Co-Supervisor |
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Dr. Mohammed A. Hefni |
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Added Date |
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Tuesday, November 28, 2023 |
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Researchers
| علي يحي بكري | Bakri, Ali Yahya | Researcher | Doctorate | |
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