41 results on '"Rabar H. Faraj"'
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2. Predicting concrete strength with waste glass using statistical evaluations, neural networks, and linear/nonlinear models
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Soran Abdrahman Ahmad, Hemn Unis Ahmed, Dler Ali Ahmed, Brwa Hamah Saeed Hamah-ali, Rabar H. Faraj, and Serwan Khwrshed Rafiq
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Civil and Structural Engineering - Published
- 2023
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3. Compressive strength of geopolymer concrete composites: a systematic comprehensive review, analysis and modeling
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Hemn Unis Ahmed, Ahmed S. Mohammed, Shaker M. A. Qaidi, Rabar H. Faraj, Nadhim Hamah Sor, and Azad A. Mohammed
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Environmental Engineering ,Civil and Structural Engineering - Published
- 2022
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4. Modeling the compressive strength of eco-friendly self-compacting concrete incorporating ground granulated blast furnace slag using soft computing techniques
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Rabar H. Faraj, Azad A. Mohammed, and Khalid M. Omer
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Health, Toxicology and Mutagenesis ,Environmental Chemistry ,General Medicine ,Pollution - Published
- 2022
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5. Soft computing techniques to predict the compressive strength of green self-compacting concrete incorporating recycled plastic aggregates and industrial waste ashes
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Rabar H. Faraj, Azad A. Mohammed, Khalid M. Omer, and Hemn Unis Ahmed
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Economics and Econometrics ,Environmental Engineering ,Environmental Chemistry ,Management, Monitoring, Policy and Law ,General Business, Management and Accounting - Abstract
Rapid urbanization and industrialization with corresponding economic growth have increased concrete production, leading to resource depletion and environmental pollution. The mentioned problems can be resolved by using recycled aggregates and industrial waste ashes as natural aggregate and cement replacement in concrete production. Incorporating different by-product ashes and recycled plastic (RP) aggregates are viable options to produce sustainable self-compacting concrete (SCC). On the other hand, compressive strength is an essential characteristic among other evaluated properties. As a result, establishing trustworthy models to forecast the compressive strength of SCC is critical to saving cost, time, and energy. Furthermore, it provides valuable instruction for planning building projects and determining the best time to remove the formwork. In this study, four alternative models were suggested to predict the compressive strength of SCC mixes produced by RP aggregates: the artificial neural network (ANN), nonlinear model, linear relationship model, and multi-logistic model. To do so, an extensive set of data consisting of 400 mixtures were extracted and analyzed to develop the models, various mixture proportions and curing times were considered as input variables. To test the effectiveness of the suggested models, several statistical evaluations, including coefficient of determination (
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- 2022
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6. Evaluating the effect of waste glass granules on the fresh, mechanical properties and shear bond strength of sustainable cement mortar
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Soran Abdrahman Ahmad, Serwan Khwrshed Rafiq, and Rabar H. Faraj
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Economics and Econometrics ,Environmental Engineering ,Environmental Chemistry ,Management, Monitoring, Policy and Law ,General Business, Management and Accounting - Published
- 2023
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7. Experimental and empirical evaluation of strength for sustainable lightweight self-compacting concrete by recycling high volume of industrial waste materials
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Rabar H. Faraj, Nadhim Hamah Sor, Aryan Far H. Sherwani, Hemn Unis Ahmed, and Nahla Hilal
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Environmental Engineering ,Volume (thermodynamics) ,Waste management ,Environmental science ,Industrial waste ,Civil and Structural Engineering - Published
- 2021
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8. Modeling the compressive strength of green mortar modified with waste glass granules and fly ash using soft computing techniques
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Soran Abdrahman Ahmad, Serwan Khwrshed Rafiq, and Rabar H. Faraj
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Environmental Engineering ,Building and Construction ,Geotechnical Engineering and Engineering Geology ,Engineering (miscellaneous) ,Civil and Structural Engineering - Published
- 2023
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9. Cleaner Production of Green Geopolymer Concrete
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Hemn Unis Ahmed, Rabar H. Faraj, Nadhim Hamah Sor, and Shaker M. A. Qaidi
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- 2023
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10. Mechanical properties and ductility behavior of ultra-high performance fiber reinforced concretes: Effect of low water-to-binder ratios and micro glass fibers
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Hakar H. Qadir, Barham H. Mohammed, Khaleel H. Younis, Rabar H. Faraj, and Aryan Far H. Sherwani
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Materials science ,020209 energy ,Glass fiber ,Water-to-Binder ratio (w/b) ,Ultra High Performance Fiber Reinforced Concrete (UHPFRC) ,Mechanical properties ,Young's modulus ,02 engineering and technology ,Fiber-reinforced concrete ,law.invention ,symbols.namesake ,Flexural strength ,law ,Fracture energy ,Ultimate tensile strength ,0202 electrical engineering, electronic engineering, information engineering ,Micro glass fibers (MGF) ,Fiber ,Composite material ,Ductility ,020208 electrical & electronic engineering ,General Engineering ,Engineering (General). Civil engineering (General) ,Compressive strength ,symbols ,TA1-2040 - Abstract
This experimental work investigates the mechanical performance and ductility behavior of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) containing high volume of micro-glass fibers (MGF). The influence of various volume fractions of MGF and two water-to-binder ratios (w/b) are investigated. These w/b ratios are 0.12 and 0.14. Based on these ratios, two groups of UHPFRC mixes were prepared and each group include seven mixes made with 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% MGF volume dosages. In total fourteen mixes were examined for the mechanical properties such as compressive strength, splitting tensile strength, modulus of elasticity, flexural strength; and the ductility behavior. It was concluded that lower w/b resulted in better mechanical performance. Also, the mixes containing 1.5% to 3% of MGF, resulted in the highest compressive strength reaching up to 160 MPa. Furthermore, the results indicated that no more strength enhancement can be achieved beyond 1.5% MGF.
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- 2021
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11. Development of eco-efficient lightweight self-compacting concrete with high volume of recycled EPS waste materials
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Nahla Hilal, Nadhim Hamah Sor, and Rabar H. Faraj
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Materials science ,Absorption of water ,Health, Toxicology and Mutagenesis ,Industrial Waste ,010501 environmental sciences ,01 natural sciences ,Industrial waste ,law.invention ,Flexural strength ,law ,Ultimate tensile strength ,Environmental Chemistry ,Recycling ,Ceramic ,Composite material ,0105 earth and related environmental sciences ,Waste Products ,Aggregate (composite) ,Construction Materials ,General Medicine ,Pollution ,Portland cement ,Compressive strength ,visual_art ,visual_art.visual_art_medium ,Polystyrenes - Abstract
Reusing the industrial waste materials is one of the main aims of sustainability and achieve the environmental protection. However, concrete is the main production for recycling waste materials and cleaning the climate. The utilization of self-consolidating lightweight concrete (SCLC) can achieve two important advantages of the structure self-weight reduction and improving workability. This paper examined the effect of waste expanded polystyrene (EPS) beads on the workability and hardened characteristics of sustainable SCLCs. Six different EPS volume fractions up to 80% replaced with normal coarse aggregate to produce SCLC mixtures with water to binder (w/b) ratio of 0.35. A total binder content of 500 kg/m3 by including 20% waste ceramic powder with 80% Portland cement and fine aggregate consist of river sand and fine ceramic with 1:1 ratio in all SCLC mixes. The workability of SCLCs was examined by slump flow time and diameter, L-box height ratio, V-funnel flow time, and segregation resistance. Moreover, the hardened properties tested at different curing periods such as compressive strength at 7, 28, and 90 days; flexural strength at 28 and 90 days; and splitting tensile strength, dry density, voids percent, water absorption, ultrasonic pulse velocity (UPV); and scanning electron microscope (SEM) at 28 days. The results verified that workability of SCLCs enhanced as EPS incorporation increased and achieved the limitations required for self-compacting concrete (SCC) while the strengths value curtailed but the compressive strength satisfied the lower value indicated by ACI for structural purposes. Depending on the water absorption and UPV, results illustrated that all produced sustainable SCLC mixtures had a good durability. Furthermore, a high linear correlation was noticed between the results.
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- 2021
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12. Microstructure characteristics, stress–strain behaviour, fresh properties, and mechanical performance of recycled plastic aggregate self-compacting concrete modified with nano-silica
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Rabar H. Faraj, Azad A. Mohammed, and Khalid M. Omer
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General Materials Science ,Building and Construction ,Civil and Structural Engineering - Published
- 2023
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13. Systematic multiscale models to predict the compressive strength of self-compacting concretes modified with nanosilica at different curing ages
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Ahmed Mohammed, Hemn Unis Ahmed, Azad A. Mohammed, Khalid M. Omer, and Rabar H. Faraj
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Coefficient of determination ,Aggregate (composite) ,Curing (food preservation) ,Materials science ,Mean squared error ,0211 other engineering and technologies ,General Engineering ,Superplasticizer ,02 engineering and technology ,Durability ,Computer Science Applications ,Types of concrete ,020303 mechanical engineering & transports ,Compressive strength ,0203 mechanical engineering ,Modeling and Simulation ,Composite material ,Software ,021106 design practice & management - Abstract
The evolution of nanotechnology brings materials with novel performance and during last year’s much attempt has been established to include nanoparticles especially nano-silica (NS) into the concrete to improve performance and develop concrete with enhanced characteristics. Generally, NS is incorporated into the self-compacting concrete (SCC) aiming to positively influence the fresh, mechanical, microstructure, and durability properties of the composite. The most important mechanical property for all types of concrete composites is compressive strength. Therefore, developing reliable models for predicting the compressive strength of SCC is crucial regarding saving time, energy, and cost-effectiveness. Moreover, it gives valuable information for scheduling the construction work and provides information about the correct time for removing the formwork. In this study, three different models including the linear relationship model (LR), nonlinear model (NLR), and multi-logistic model (MLR) were proposed to predict the compressive strength of SCC mixtures made with or without NS. In this regard, a comprehensive data set that consists of 450 samples were collected and analyzed to develop the models. In the modeling process, the most important variables affecting the compressive strength such as NS content, cement content, water to binder ratio, curing time from 1 to 180 days, superplasticizer content, fine aggregate content, and coarse aggregate content were considered as input variables. Various statistical assessments such as Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), Scatter Index (SI), OBJ value, and the coefficient of determination (R2) were used to evaluate the performance of the proposed models. The results indicated that the MLR model performed better for forecasting the compression strength of SCC mixtures modified with NS compared to other models. The SI and OBJ values of the MLR model were 18.8% and 16.7% lower than the NLR model, indicating the superior performance of the MLR model. Moreover, the sensitivity analysis demonstrated that the curing time is the most affecting variable for forecasting the compressive strength of SCC modified with NS.
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- 2021
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14. Effect of medium-density fiberboard wastes ash on calcium silicate hydrate crystal of concrete
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Hamid Kazemi, Rabar H. Faraj, Wrya Abdullah, Shahriar Shahbazpanahi, and Amir Mosavi
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Waste Products ,Construction Materials ,Silicates ,Management, Monitoring, Policy and Law ,Calcium Compounds ,Waste Management and Disposal - Abstract
Due to the high consumption of Medium-density fiberboard (MDF), waste products of this material are growing worldwide. In this research, the feasibility of using Medium-density fiberboard waste ash (MDFWA) as part of cement in concrete was investigated. For this purpose, 0, 5, 10, 15, 20, and 25% of the cement in concrete was substituted with MDFWA. For all design mixes, the water/blind ratio and the volume of aggregates were same. The slump, compressive strengths, SEM, EDX, TGA, DSC, and FTIR tests were conducted on the samples. At 28 days, the results demonstrated that the compressive strength of the sample containing 20% MDFWA increased by 13.6% compared to the control sample. Furthermore, the microstructure of the concrete show that the voids of the sample containing 20% MDFWA reduced compared to the control sample and also more calcium silicate hydrate (C-S-H) crystal formed.
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- 2022
15. Feasibility study on the use of tagouk ash as pozzolanic material in concrete
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Shahriar Shahbazpanahi, Mahmood Seraji, Rabar H. Faraj, and Salar Manie
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Cement ,Economics and Econometrics ,Environmental Engineering ,Materials science ,Scanning electron microscope ,020209 energy ,Metallurgy ,Infrared spectroscopy ,02 engineering and technology ,Pozzolan ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,General Business, Management and Accounting ,Compressive strength ,Properties of concrete ,0202 electrical engineering, electronic engineering, information engineering ,Environmental Chemistry ,Fourier transform infrared spectroscopy ,Porosity ,0105 earth and related environmental sciences - Abstract
This paper reports an experimental study on the micro-structure as well as mechanical properties of concrete mixes with partial replacement of cement by Tagouk ash as a type of natural Pozzolan. Partial cement replacement by waste natural materials such as Tagouk ash would be a promising solution toward reducing greenhouse gases emissions as well as environmental pollutions. Typically found in rocky environments, Tagouk is a species of wild trees belonging to the Cannabaceae family of plants. Tagouk normally grows up to about 25 m in height and 40 cm in diameter and contains high amounts of minerals including silica and calcium, making it an ideal candidate to be used as a pozzolanic supplement in concrete. In this research, the effects of partial replacement of cement with Tagouk ash by the amounts of 5, 10, 15, and 20% of the cement weight in the mix were studied. In all mixes, the water-to-cement (W/C) ratio was considered to be constant and equals to 0.4. Also, the amount of aggregates was constant for all design mixes. The compressive strengths of all samples at the ages of 7, 28, and 90 days were recorded. Scanning of specimens was performed by using scanning electron microscope (SEM) to investigate the micro-structure, too. Energy-dispersive X-ray spectroscopy analysis (EDX), X–ray diffraction (XRD), thermo-gravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FTIR) of the samples were also studied. Results show significant enhancement in compressive strength of the concrete samples with 15% TA replacement by approximately 48% and 43% at 28 and 90 days, respectively. Moreover, the results of SEM as well as those of EDX spectroscopy demonstrate that Tagouk ash results in reducing the porosity of concrete and also forming secondary C–S–H products. It appears that Tagouk ash is an efficient natural Pozzolan for partial replacement with cement in concrete.
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- 2021
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16. List of contributors
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Bahira Abdulsalam, Hemn Unis Ahmed, Rassoul Ajalloeian, Ahmed Al-Mansour, U. Johnson Alengaram, Ali Alsalman, Farshad Ameri, Lateef N. Assi, Erfan Atabakhsh, Babak Behforouz, I. Blanco, Mahdi Boroujeni, Sara Boudali, Ayobami Busari, Kealy Carter, Xueqin Chen, Raffaele Cioffi, Francesco Colangelo, F. Convertino, Luigi Cossentino, Sina Dadsetan, Shaswat Kumar Das, Jorge de Brito, Cristoforo Demartino, G. Dhinakaran, N. Divyah, Qiao Dong, A.M. Elkordi, Adel ElSafty, Beatriz Leão Evangelista de Lara, Flora Faleschini, Rabar H. Faraj, Ilenia Farina, Akvan Gajanayake, Stephan Godbout, Diofantos Hadjimitsis, Hisham Hafez, Hunar F. Hama ali, Ghasan Fahim Huseien, Mohammad Jamalimoghadam, Malaya Kumar Jena, Misagh Karimzadeh, Alireza Kashani, Syed Minhaj Saleem Kazmi, J.M. Khatib, R.S. Krishna, Rawaz Kurda, Nicholas Kyriakides, Mohamed Lachemi, Jie Li, Le Li, Jiahan Liu, Tingfeng Lu, M.M. Machaka, Aziz Hasan Mahmood, Obaid Mahmoodi, Natt Makul, Juan M. Manso, Subhabrata Mishra, Ivan Moccia, Muhammad Junaid Munir, Syed Mohammed Mustakim, Kyriacos Neocleous, Renato Olivares, Vanesa Ortega-López, Johann Palacios, Daman K. Panesar, Carmenlucia Santos Giordano Penteado, Antonella Petrillo, Thomaida Polydorou, Sébastien Poncet, R. Prakash, Salvatore Puca, Tanvir S. Qureshi, Sudharshan N. Raman, Antonio Ramondo, Víctor Revilla-Cuesta, Laís Peixoto Rosado, Marco Ruggiero, Mohammad Saberian, Amirhomayoun Saffarzadeh, Mustafa Şahmaran, Trilochan Sahu, Cinzia Salzano, G. Scarascia-Mugnozza, E. Schettini, Kwok Wei Shah, Aryan Far H. Sherwani, Parham Shoaei, Hocine Siad, José Silvestre, Marta Skaf, Ahmed Soliman, C. Subramanian, Marta Travaglioni, Ankit Kumar Tripathy, S.S. Vivek, G. Vox, Jiyang Wang, Yu-Fei Wu, Jin Xia, Jinyi Xu, Mariano Angelo Zanini, Seyed Alireza Zareei, Qiang Zeng, Guomin Zhang, Jingxuan Zhang, Runxiao Zhang, and Paul Ziehl
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- 2022
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17. Fresh and mechanical properties of concrete made with recycled plastic aggregates
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Rabar H. Faraj, Hemn Unis Ahmed, Hunar F. Hama ali, and Aryan Far H. Sherwani
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- 2022
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18. Ultra-high-performance fiber-reinforced concrete. Part V: Mixture design, preparation, mixing, casting, and curing
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Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Rabar H. Faraj, Samadar S. Majeed, Ahmed S. Mohammed, Wael Emad, Bassam A. Tayeh, and Afonso R.G. Azevedo
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Materials Science (miscellaneous) - Published
- 2022
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19. Ultra-high-performance fiber-reinforced concrete. Part I: Developments, principles, raw materials
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Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Rabar H. Faraj, Ahmed S. Mohammed, Wael Emad, Bassam A. Tayeh, and Afonso R.G. Azevedo
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Materials Science (miscellaneous) - Published
- 2022
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20. Ultra-high-performance fiber-reinforced concrete. Part III: Fresh and hardened properties
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Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Wael Emad, Rabar H. Faraj, Ahmed S. Mohammed, Bassam A. Tayeh, and Afonso R.G. Azevedo
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Materials Science (miscellaneous) - Published
- 2022
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21. Ultra-high-performance fiber-reinforced concrete. Part II: Hydration and microstructure
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Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Rabar H. Faraj, Ahmed S. Mohammed, Wael Emad, Bassam A. Tayeh, and Afonso R.G. Azevedo
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Materials Science (miscellaneous) - Published
- 2022
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22. Ultra-high-performance geopolymer concrete: A review
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Shaker M.A. Qaidi, Dawood Sulaiman Atrushi, Ahmed S. Mohammed, Hemn Unis Ahmed, Rabar H. Faraj, Wael Emad, Bassam A. Tayeh, and Hadee Mohammed Najm
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General Materials Science ,Building and Construction ,Civil and Structural Engineering - Published
- 2022
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23. Compressive strength of geopolymer concrete modified with nano-silica: Experimental and modeling investigations
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Hemn Unis Ahmed, Ahmed S. Mohammed, Rabar H. Faraj, Shaker M.A. Qaidi, and Azad A. Mohammed
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Materials Science (miscellaneous) - Published
- 2022
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24. Self-compacting concrete composites modified with nanoparticles: A comprehensive review, analysis and modeling
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Rabar H. Faraj, Azad A. Mohammed, and Khalid M. Omer
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Mechanics of Materials ,Architecture ,Building and Construction ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering - Published
- 2022
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25. Performance of Self-Compacting mortars modified with Nanoparticles: A systematic review and modeling
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Rabar H. Faraj, Hemn Unis Ahmed, Serwan Rafiq, Nadhim Hamah Sor, Dalya F. Ibrahim, and Shaker M.A. Qaidi
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- 2022
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26. An experimental investigation on the nano-fly ash preparation and its effects on the performance of self-compacting concrete at normal and elevated temperatures
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Yusra M. Al-Obaidi, Nahla Hilal, and Rabar H. Faraj
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Environmental Engineering ,Compressive strength ,Materials science ,Flexural strength ,Scanning electron microscope ,Fly ash ,Nano ,Environmental Chemistry ,Nanoparticle ,Bioengineering ,Composite material ,Microstructure ,Elastic modulus - Abstract
Previous research regarding the performance of self-compacting concrete (SCC) incorporating nano-fly ash (NFA), especially after exposure to elevated temperatures, is scarce. Therefore, this experimental research was conducted to investigate the influence of NFA particles on the performance of SCC at normal and elevated temperatures. The effects of NFA particles were also compared with the influence of fly ash (FA) particles at the same replacement percentages. The experimental program was managed at two stages. At the first stage, the microparticles of FA were transformed into nanoparticles using electric milling process. The size, shape, and consistency of the FA and NFA particles were characterized using scanning electron microscopy. In the second stage, experimental tests were performed to examine the influences of FA and NFA particles on the performance and characteristics of SCC. The investigated parameters included fresh density, dry density, T50 slump flow time, slump flow diameter, elastic modulus, ultrasonic pulse velocity (UPV), and compressive as well as flexural strength. Furthermore, the residual compressive strength, weight loss, and UPV after exposing the concrete samples to 700 °C were also investigated. The results showed that addition of FA and NFA can cause a reduction in the workability as well as flowability of SCC mixtures. On the other hand, the transformation of FA to NFA significantly enhanced the microstructure of the SCC, which led to the enhancement of its mechanical properties and boosted the resistance of the SCC to high temperatures. The outcomes of this study also illustrated that through transforming the particles of FA from microscale to nanoscale, a sustainable and high-performance SCC can be produced.
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- 2020
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27. Mechanical properties and fracture parameters of ultra high performance steel fiber reinforced concrete composites made with extremely low water per binder ratios
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Hakar H. Qadir, Barham H. Mohammed, Khaleel H. Younis, Rabar H. Faraj, and Aryan Far H. Sherwani
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Materials science ,General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Young's modulus ,Fiber-reinforced concrete ,law.invention ,symbols.namesake ,Compressive strength ,Flexural strength ,law ,Ultimate tensile strength ,symbols ,General Earth and Planetary Sciences ,General Materials Science ,Fiber ,Composite material ,Ductility ,Elastic modulus ,General Environmental Science - Abstract
This study examines the effects of high-volume micro-steel fibers (MSF) content on the mechanical properties, fracture parameters, and ductility of ultra-high performance fiber reinforced concrete (UHPFRCs). The MSFs used in this experiment had an aspect ratio of 37.5 with average length of 6 mm. The investigated parameters include very low water/binder (w/b) ratio and fiber content. Sixteen UHPFRC mixes were examined, eight mixes were made with w/b of 0.12 and eight fiber contents (0%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5, 4%) while the other eight mixes were made with the same fiber contents but with w/b of 0.14. The UHPFRC mixes were examined for various strengths (compressive, splitting tensile, flexural), elastic modulus, and fracture parameters. The experimental results showed that the mixture with 4% of MSFs content and 0.12 w/b ratio exhibited a compressive strength of more than 160 MPa, splitting tensile strength higher than 12 MPa, and modulus of elasticity greater than 43 GPa. Moreover, the results also demonstrated that with increasing MSFs content from 0 to 4% the load–displacement behavior, ductility, and all other fracture parameters were improved significantly.
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- 2020
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28. Properties of eco-friendly pervious concrete containing polystyrene aggregates reinforced with waste PET fibers
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Abdulkader Ismail Al-Hadithi, Taghreed Khaleefa Mohammed Ali, Nahla Hilal, and Rabar H. Faraj
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Environmental Engineering ,Materials science ,Pervious concrete ,0211 other engineering and technologies ,02 engineering and technology ,Building and Construction ,Geotechnical Engineering and Engineering Geology ,Compression (physics) ,Environmentally friendly ,chemistry.chemical_compound ,Compressive strength ,chemistry ,Flexural strength ,021105 building & construction ,Polystyrene ,Fiber ,Composite material ,Porosity ,Engineering (miscellaneous) ,021101 geological & geomatics engineering ,Civil and Structural Engineering - Abstract
A huge amount of expanded polystyrene (EPS) and PET plastics are produced every year all around the world. However, if not treated properly, after their consumption, EPS and PET caused numerous environmental problems. Therefore, the utilization of these wastes in concrete production can contribute to the sustainability of construction materials. This experimental study aims to investigate the behavior and properties of pervious concrete incorporating both EPS aggregates and waste PET fibers. A total of ten concrete mixtures were designed with different percentages of PET fibers and the same amount of EPS content. The investigated parameters included: abrasion resistance, dry density, compression as well as flexural strength, porosity ratio and water permeability coefficient. From the results obtained in this study, it has been shown that the proposed mixes are reliable to use in the construction field. The compressive strength, abrasion resistance and density decreased by incorporating EPS and PET fibers. However, the flexural strength increased by using PET fibers up to 1% in volume. On the other hand, the porosity ratio and the water permeability coefficient increased through the addition of PET fiber. The empirical models among different properties were also provided. This experimental study can be contributed to promote sustainable construction materials as mixtures contained a considerable amount of waste materials.
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- 2020
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29. The behavior of sustainable self-compacting concrete reinforced with low-density waste Polyethylene fiber
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Nadhim Hamah Sor, Taghreed Khaleefa Mohammed Ali, Kolimi Shaiksha Vali, Hemn Unis Ahmed, Rabar H. Faraj, Naraindas Bheel, and Amir Mosavi
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Biomaterials ,Polymers and Plastics ,Metals and Alloys ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
Sustainable concrete production and recycling the construction wastes are of utmost importance for today’s sustainable urban development. In this study, low-density polyethylene waste was recycled in the form of fibers (LDPF) to produce eco-friendly fiber-reinforced sustainable self-compacting concrete (SCC). The content of LDPF ranged from 0.5% to 3.5% at a raise of 0.5% of the mix’s volume. The SCC’s features in fresh and hardened states were tested. The slump flow diameter, T500, V-funnel, and L-box ratio were measured for the fresh properties. The compressive, splitting tensile and flexural strengths were tested at the age of 28 days. However, the outcomes indicated that LPDF had some negative effect on the workability features, but all the results of SCC mixtures were within the standard limitations of SCC except that related to the L-box, which satisfied the standards up to 2% of LDPF. However, the incorporation of LDPF enhanced the mechanical properties, especially the flexural strength. The optimum ratio for the LPDF was 2%, which satisfies the required workability and the highest strength with modulus of elasticity. The thermal conductivity decreased with increasing LDPF content in the SCC mixtures.
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- 2022
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30. Stabilization of problematic soil by utilizing cementitious materials
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Shvan Mohammad, Aryan Far H. Sherwani, Sedad Kurdo, Rabar H. Faraj, Arsalan Mahmoodzadeh, Shokrollah Zare, and Ako Daraei
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Cement ,Environmental Engineering ,Gypsum ,Settlement (structural) ,Building and Construction ,engineering.material ,Geotechnical Engineering and Engineering Geology ,Arid ,Human settlement ,Semi-arid climate ,Soil water ,engineering ,Environmental science ,Geotechnical engineering ,Cementitious ,Engineering (miscellaneous) ,Civil and Structural Engineering - Abstract
Due to the urbanization and the need to develop the transportation services, it is inevitable to deal with ground characterized by undesirable geotechnical properties. The problematic soils are divided into swelling soils, collapsible and dispersive soils. The arid to semiarid climate of the Middle East has provided the conditions for the expansion of them. The presence of problematic soils in Iraqi Kurdistan has given rise to many damage to the construction projects of this region. The under-construction road of Gali Ali Bag designed in the vicinity of the Erbil-Haji Omeran highway in Iraqi Kurdistan was faced with pavement settlement and collapse of side slopes due to the passing through the collapsible soils. The presence of collapsible soils in the vicinity of the aforesaid international highway grew concerns about the occurrence of such settlements during its construction. Therefore, how to treat or reduce the collapsibility, especially by the use of practical methods on the site, was addressed as one of the major challenges. In this study, the behavior of treated host soil by four cementitious materials including cement, quicklime, gypsum and NaCl was determined by applying indirect and direct methods. The results show that the addition of 6% quicklime will have the greatest effect on the reduction in collapsibility. After implementing this plan on the site, the collapsibility index decreased by an average of 2.92%.
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- 2019
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31. Optimization of the outlet portal of Heybat Sultan twin tunnels based on the value engineering methodology
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Rabar H. Faraj, Ako Daraei, Shokrollah Zare, Qobad Kalhor, Arsalan Mahmoodzadeh, and Aryan Far H. Sherwani
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Computer science ,General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Excavation ,Plan (drawing) ,Civil engineering ,Factor of safety ,Supporting system ,Slope stability ,Sustainable design ,General Earth and Planetary Sciences ,General Materials Science ,Value engineering ,Iraqi kurdistan ,General Environmental Science - Abstract
Due to uncertainties in determining the geotechnical parameters, it is inevitable to change the supporting system and excavation method during the tunnel construction projects. Such changes will in many cases lead to an increase in the foreseen time and cost. Since the beginning of the 1960s, value engineering (V.E.) was raised based on three principles of safety, cost optimization and sustainable design. Iraqi Kurdistan has had an increasing trend in design and implementation of development projects since 2008, but high safety factors considered to compensate for uncertainties in geotechnical parameters has imposed high construction costs to these projects. The design of more than 70 km of tunnels, 212 dams and more than 500 km of highways under construction in this region necessitates performing applicable case studies on the implementation of V.E. in these development projects. The Heybat Sultan twin tunnels project is being constructed as a part of the Erbil–Koya–Sulaymaniyah highway in Iraqi Kurdistan. Preliminary studies showed that the outlet portals of these tunnels had been designed with a high factor of safety. Hence, the decision was made to make changes based on V.E. principles prior to the commencement of the excavations and at the time of site mobilization. For this purpose, the most optimal method statement was selected for the outlet portal, and then the slope stability was evaluated using numerical analysis. By implementing the optimized design, the factor of safety was increased from 1.27 to 2.48 and the corresponding construction costs was decreased for 2.4 million USD compared to the original plan.
- Published
- 2019
- Full Text
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32. Use of recycled fibers in concrete composites: A systematic comprehensive review
- Author
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Nahla Hilal, Rabar H. Faraj, Azad A. Mohammed, Aryan Far H. Sherwani, and Hemn Unis Ahmed
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Municipal solid waste ,Materials science ,Waste management ,Mechanical Engineering ,Environmental pollution ,02 engineering and technology ,Reuse ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Slump ,Compressive strength ,Properties of concrete ,Flexural strength ,Mechanics of Materials ,Ultimate tensile strength ,Ceramics and Composites ,Composite material ,0210 nano-technology - Abstract
Municipal solid waste materials are growing worldwide due to human consumption. Nowadays, a different type of goods on large-scale is produced in the factories which is going to generate numerous amount of solid waste materials in the near future. Therefore, the management of these solid waste materials is a great concern around the world. Inadequate landfill, environmental pollution and its financial burden on relevant authorities, recycling and utilization of waste materials have a significant impact compared to disposing them. Studies have been done to reuse of waste materials as one of the elements of concrete composites. Each of the elements gives the concrete strength; however, the reuse of these wastes not only makes the concrete economical and sustainable, but also helps in decreasing environmental pollution. There are a number of different types of waste materials such as plastics, carpets, steels, tires, glass, and several types of ashes. In this paper, a comprehensive review was carried out on the influence of recycled plastic fibers (RPFs), recycled carpet fibers (RCFs) and recycled steel fibers (RSFs) on the fresh, mechanical and ductility properties of concrete. The previous studies were investigated to highlight the effects of these waste product fibers on the most important concrete properties such as slump, compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, ultrasonic pulse velocity, energy absorption, ductility, and toughness. In this regard, more than 200 published papers were collected, and then the methods of preparation and properties of these recycled fibers (RF) were reviewed and analyzed. Moreover, empirical models using mechanical properties were also developed. As a result, RPFs, RCFs and RSFs could be used safely in concrete composites due to it is satisfactory fresh, physical and mechanical properties.
- Published
- 2021
- Full Text
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33. Strength, abrasion resistance and permeability of artificial fly-ash aggregate pervious concrete
- Author
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Ako Daraei, Rabar H. Faraj, Khaleel H. Younis, and Aryan Far H. Sherwani
- Subjects
Porous concrete ,Materials science ,Aggregate (composite) ,Pervious concrete ,Abrasion (mechanical) ,Materials Science (miscellaneous) ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Abrasion resistance ,Permeability ,0201 civil engineering ,law.invention ,Permeability (earth sciences) ,Portland cement ,Compressive strength ,law ,Fly ash ,021105 building & construction ,Ultimate tensile strength ,TA401-492 ,Composite material ,Artificial cold bonded fly ash aggregate ,Materials of engineering and construction. Mechanics of materials - Abstract
The objective of this study is to utilize artificial cold bonded fly ash aggregate (AFA) in pervious concrete to produce a sustainable, and permeable concrete. The AFA were manufactured through cold bonding pelletization of fly ash (90 %) and Portland cement (10 %) in an inclined pan at ambient temperature. In this study, pervious concrete is manufactured by replacing the natural aggregates (NA) with AFA in five levels of replacements 0–100% with 25 % increments of the total aggregate’s volume. Two different concrete series were manufactured at 0.27 and 0.32 water-to-cement ratios (w/c). Totally, 10 pervious concretes were manufactured in this study. The utilized NA and AFA were uniformly graded and ranged 12.5 mm to 8 mm. In this study, the dry density and content of voids were determined. Furthermore, for the produced pervious concretes some tests were conducted such as compressive strength, splitting tensile, permeability and abrasion resistance. Besides, GLM-ANOVA as a statistical tool was employed to examine the effective parameter(s) on the properties of pervious concrete made using AFA. The results showed that with replacing the natural aggregate with 100 % AFA, the dry density of pervious concretes has decreased up to 22.4 % and the content of void and abrasion value has increased up to 20.8 %, and 153.8 %, respectively, for 0.27 w/c. In addition, the full replacement of NA with AFA resulted in a decrease of 51.5 % and 57.2 % in compressive strength and splitting tensile values made with w/c of 0.27. While, utilizing AFA significantly enhanced the permeability coefficient of the pervious concrete reaching maximum value of 10.27 mm/sec at w/c of 0.32.
- Published
- 2021
- Full Text
- View/download PDF
34. Rheological behavior and fresh properties of self-compacting high strength concrete containing recycled PP particles with fly ash and silica fume blended
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Aryan Far H. Sherwani, Lamyaa Hama Jafer, Rabar H. Faraj, and Dalya F. Ibrahim
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Polypropylene ,Materials science ,Aggregate (composite) ,Silica fume ,0211 other engineering and technologies ,Environmental pollution ,02 engineering and technology ,Building and Construction ,law.invention ,Portland cement ,chemistry.chemical_compound ,Compressive strength ,chemistry ,Rheology ,Mechanics of Materials ,law ,Fly ash ,021105 building & construction ,Architecture ,021108 energy ,Composite material ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering - Abstract
Solid waste management can be regarded as one of the major environmental concerns across the globe. Annually, substantial quantities of plastics are produced. The utilization of this waste can result in a variety of huge problems such as health hazards, disposal, and environmental pollution. In this paper, the workability and rheological characteristics of self-compacting high strength concrete (SCHSC) made with recycled polypropylene plastic particles (RPPP) with fly ash (FA) and silica fume (SF) are investigated. The SCHSC was employed by replacing the medium-coarse aggregate (MCA) with five percentages of RPPP contents at 0%, 10%, 20%, 30%, and 40% by volume. The first group of mixtures contained 20% FA and 80% Portland cement (PC). On the other hand, the second group of the mixes made with 20% FA, 10% SF, and 70% PC. To investigate such workability-related properties as slump flow diameter (SFD), T50 slump flow time (SFT), V-funnel flow time (VFT), L-box height ratio (LHR), and L-box T200 and T400 flow times, 10 concrete mixtures were produced and tested. ICAR rheometer in the rheological testing of fresh SCHSCs was used to determine the rheological parameters. For all mixtures, the compressive strength was measured at 28 days. With respect to the experimental results of the current study, the Herschel-Bulkley and modified Bingham models can provide well defined rheological representations for SCHSC with RPPP. The mixtures containing a combination of FA, SF, and RPPP can have better fresh characteristics compared to those without SF. Moreover, all produced SCHSC mixtures can be at a satisfactory level with the limitations required for the fresh properties of SCC.
- Published
- 2021
- Full Text
- View/download PDF
35. Fresh Behavior and Hardened Properties of Self-Compacting Concrete Containing Coal Ash and Fly Ash as Partial Replacement of Cement
- Author
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Noor A. Rajab, Rabar H. Faraj, and Nahla Hilal
- Subjects
Cement ,Materials science ,Fly ash ,Metallurgy - Abstract
Due to the higher price of cement compared to other concrete ingredients, the problems associated with greenhouse gases emissions during its production and its high popularity have arisen concerns in its substitution with other supplementary cementitious materials (SCMs). In this regard, the current experimental program was established to investigate the fresh and hardened performance of self-compacting concrete (SCC) made with coal ash (CA) and fly ash (FA) as fractional substitution of cement. In this paper an attempt was made to use the remaining CA from the barbecue process of the restaurants from Fallujah city, Iraq. A total number of 7 concrete mixes were prepared with unchanged (w/b) ratio of 0.37 and total cementitious content of 450 kg/m3. Reference mix was produced by using 100% cement without FA or CA. Then, other mixtures were batched with 10%, 20% and 30% (by weight) replacement of cement by FA and CA, respectively. The results illustrated that, in contrast to the FA, the CA has negative influences on the fresh properties of SCC but the results still meet the criteria for the fresh behavior of SCC. On the other hand, the inclusion of CA was significantly improved the strength and water absorption of SCC. Sustainable high strength SCC can be produced due to the addition of CA.
- Published
- 2020
- Full Text
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36. Decision-making in tunneling using artificial intelligence tools
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Arsalan Mahmoodzadeh, Mokhtar Mohammadi, Ako Daraei, Aryan Far H. Sherwani, Rebaz Mohammed Dler Omer, and Rabar H. Faraj
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business.industry ,0211 other engineering and technologies ,Mode (statistics) ,02 engineering and technology ,Building and Construction ,Schedule (project management) ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Tunnel construction ,Support vector machine ,Initial training ,Kriging ,Ground-penetrating radar ,Artificial intelligence ,business ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
Given the frequent cost overruns and schedule delays associated with tunnel construction projects, it is imperative that a detailed estimation of both be developed and considered prior to starting construction. To this end, two artificial intelligence tools of Gaussian Process Regression (GPR) and Support Vector Regression (SVR) were used to forecast geology, construction time and construction costs of a road tunnel project. The initial training datasets applied in the prediction tools were accessed from the previously-constructed road tunnels and the pre-existing observations of the tunnel under consideration. Also, during the tunnel construction, more training datasets obtained in the constructed parts were added to the previous datasets and the pre-constructed predictions of the GPR and SVR tools were updated. Lastly, comparing the predictions made by the GPR and SVR tools with the actual mode of the tunnel, and comparing the pre-updating predictions with the post-updating ones, it was concluded that, the GPR and SVR tools have presented very good predictions and they have reduced the uncertainties regarding geology and construction time and costs to an acceptable level. But, the GPR tool has presented more accurate results than the SVR tool. Also, the updating procedure can significantly increase the predictions accuracy.
- Published
- 2020
- Full Text
- View/download PDF
37. Feasibility study on the use of shell sunflower ash and shell pumpkin ash as supplementary cementitious materials in concrete
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Rabar H. Faraj, Shahriar Shahbazpanahi, and Shahram ShahbazPanahi
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Cement ,Materials science ,Scanning electron microscope ,0211 other engineering and technologies ,02 engineering and technology ,Building and Construction ,Pozzolan ,Microstructure ,Slump ,Compressive strength ,Mechanics of Materials ,021105 building & construction ,Architecture ,Pozzolanic reaction ,021108 energy ,Cementitious ,Composite material ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering - Abstract
This study proposes that Shell Sunflower Ash (SSA) and Shell Pumpkin Ash (SPA) partially replace cement in concrete as pozzolanic materials. To trace the chemical composition of raw SSA and SPA, X–Ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized. Cement was replaced with 5, 10, 15 and 20% of the SSA and SPA. The slump of fresh concrete, elastic modulus, compressive strength, ultrasonic pulse velocity (UPV) test, SEM, energy dispersive x–ray (EDX), XRD and thermo-gravimetric analysis (TGA) of the sample were studied. Pozzolanic reaction with percentage of SSA and SPA was lower than the control specimen in the early ages. The addition of the SSA to the mix by up to 15% increased the compressive strength of the sample by 27.3% at 28 days. The SEM and EDX results illustrate the replacement of cement with the SSA and the SPA can improve the microstructure of the mixtures at 28 days. The SEM also showed that the addition of 15% the SSA and the SPA decreased the voids in the matrix. XRD and TAG results also demonstrated the effect of SSA and the SPA on reduction of CH content due to pozzolanic reactions. The result show that use of the SSA and SPA as replacement of cement is feasible.
- Published
- 2020
- Full Text
- View/download PDF
38. Use of recycled plastic in self-compacting concrete: A comprehensive review on fresh and mechanical properties
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Hunar Farid Hama Ali, Bedar R. Hassan, Rabar H. Faraj, Aryan Far H. Sherwani, and Hogr Karim
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Materials science ,Waste management ,Plastic recycling ,0211 other engineering and technologies ,Plastic materials ,New materials ,02 engineering and technology ,Building and Construction ,Reuse ,Environmentally friendly ,Mechanics of Materials ,021105 building & construction ,Architecture ,Plastic waste ,021108 energy ,Cementitious ,Mortar ,Safety, Risk, Reliability and Quality ,Civil and Structural Engineering - Abstract
Due to manufacturing processes, municipal solid wastes and service industries, huge amount of waste materials are generated. Recently, a considerable growth in the plastic consumption across the globe can be observed. This has caused enormous quantities of plastic-related waste. Producing new materials such as mortar or concrete from recycling of plastic waste (PW) seems to be one of the best solution for disposing of PW since it is considered to be environmentally and economically advantageous. In modern constructions, self-compacting concrete (SCC) is employed as a main cementitious material, which functions complex formworks without mechanical vibrations with high segregation resistance and greater deformability. Reuse of recycled plastic (RP) in SCC mixes can provide an environmentally friendly and sustainable construction material. Therefore, it has been an ongoing topic for several researches, and a large number of studies investigating the properties of SCC comprising waste and RP materials have been conducted.- In this study, the current and most recent literatures considering plastic recycling method and the influence of plastic materials on the fresh and mechanical properties of SCC are summarized. So that a comprehensive review can be provided in which the reviewed studies are categorized into sub groups based on whether they dealt with SCC containing plastic aggregates (PAs) or plastic fibers (PFs). Furthermore, the effect of RP on the fresh and mechanical properties of various self-compacting composites like self-compacting mortar (SCM), self-compacting high strength concrete (SCHSC) and self-compacting light weight concrete (SCLC) have been reviewed to illustrate the differences with normal SCC. The empirical relationships among various mechanical properties were also developed. Based on the obtained results from previous studies, recycled plastic self-compacting concrete (RPSCC) can be used for structural applications due to its satisfactory fresh and mechanical properties. Moreover, this type of concrete is environmentally friendly and sustainable product due to replacing the natural aggregates (NA) with plastic materials.
- Published
- 2020
- Full Text
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39. A Case Study: Effect of Soil-Flexibility on the Seismic Response of Reinforced Concrete Intermediate-Rise Regular Buildings in Halabja City
- Author
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Rabar H. Faraj
- Subjects
Flexibility (engineering) ,business.industry ,Structural engineering ,business ,Reinforced concrete ,Geology - Published
- 2018
- Full Text
- View/download PDF
40. Mechanical, fracture and durability properties of self-compacting high strength concrete containing recycled polypropylene plastic particles
- Author
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Rabar H. Faraj, Ako Daraei, and Aryan Far H. Sherwani
- Subjects
Materials science ,Aggregate (composite) ,Silica fume ,0211 other engineering and technologies ,02 engineering and technology ,Building and Construction ,law.invention ,Portland cement ,Compressive strength ,Flexural strength ,Mechanics of Materials ,law ,021105 building & construction ,Architecture ,Ultimate tensile strength ,021108 energy ,Cementitious ,Composite material ,Safety, Risk, Reliability and Quality ,Ductility ,Civil and Structural Engineering - Abstract
This study focuses on the mechanical, fracture and durability characteristics of self-compacting high-strength concrete (SCHSC) containing recycled polypropylene plastic particles (RPPP) with and without silica fume (SF). The designation of the two different sets of SCHSC containing plastic particles were used on the basis of a constant water–cementitious substance (w/cm) ratio of 0.32 and a total cementitious materials content of 550 kg/m3. The first set of mixtures included binary cementitious blends of 20% fly ash (FA) and 80% Portland cement (PC). However, the second series of the mixtures incorporated ternary cementitious blends of 20% FA, 10% SF and 70% PC. To produce the concretes, medium size aggregate was replaced with RPPP at five designated percentages of 0%, 10%, 20%, 30% and 40% by volume in both sets of concretes. Totally, 10 mixtures were produced and tested for mechanical, fracture and durability properties such as elastic modulus, compressive and splitting tensile strength, flexural strength, sorptivity, chloride ion permeability, gas permeability and fracture energy. The tests were carried out 28 and 90 days after casting. The test results showed that the use of RPPP significantly improved the fracture and ductility properties, whereas aggravated other measured properties of SCHSCs. However, with the addition of SF all mechanical and durability characteristics remarkably enhanced. The results also demonstrated that SCHSC with compressive strength higher than 70 MPa at 90 days was produced by using RPPP content up to 40% replacement level by total medium aggregate volume, and 10% SF.
- Published
- 2019
- Full Text
- View/download PDF
41. Updating ground conditions and time-cost scatter-gram in tunnels during excavation
- Author
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Mokhtar Mohammadi, Ako Daraei, Arsalan Mahmoodzadeh, Rabar H. Faraj, Tarik A. Rashid, Aso Mohammad Darwesh, and Aryan Far H. Sherwani
- Subjects
Procurement ,Work (electrical) ,Control and Systems Engineering ,Computer science ,Code (cryptography) ,Excavation ,Building and Construction ,Bidding ,Industrial engineering ,Relevant information ,Time cost ,Civil and Structural Engineering ,Learning effect - Abstract
Minimizing uncertainties is an important issue among the significant discussions pertaining to the project design and planning. Usually, the uncertainties in subsurface projects arise from the unknown ground conditions that may cause the designer to fail to consider all the potential issues prone to occur during the construction procedure. Total time and costs uncertainties can be considered as the most important uncertainties during the planning and excavation of a tunnel project that is directly connected with cognition of the subsurface conditions. This work presents an updating procedure and associated code, which allows one to refine predictions during construction. Updating does not only involve replacing the original prediction by actual data from the excavation but also includes a learning effect. The updating uses information from the actual excavation to arrive at an improved prediction for the unexcavated part. Updating the ground conditions and time-cost scatter-gram in tunnels during excavation is a tool, which helps the user refine input parameters by deriving relevant information from construction data and presenting it together with original input. In this paper, an example project shows that the updating result has a significant impact on the precision of the prediction and reduces the uncertainty about ground conditions and construction time and cost of the tunnel substantially. It facilitates both the owners and the contractors to be aware of the risk they should carry before construction of the unexcavated part, and it is useful for both tendering and bidding.
- Published
- 2019
- Full Text
- View/download PDF
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