Article
Construction & Building Technology
Hamdy Shehab, Ahmed Eisa, Ahmed Mohamed Wahba, Peter Sabol, Dusan Katunsky
Summary: The use of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) has increased in civil engineering, particularly in megastructure applications. UHPFRC provides high strength and durability, allowing for reconstruction and extension of a structure's lifespan. Adding fibers to UHPFRC enhances its ductility and fracture toughness, opening up new application areas. This study investigates the behavior of reinforced concrete columns strengthened with UHPFRC jackets, finding that vertical grooving improves load capacity compared to horizontal grooving or no grooving.
Article
Mechanics
Jacopo Donnini, Giovanni Lancioni, Gianluca Chiappini, Valeria Corinaldesi
Summary: This study investigated the uniaxial tensile behavior of soft cast UHPFRC by varying the amount of hooked steel fibers, using direct tensile tests and Digital Image Correlation. Numerical simulations with a phase-field model were conducted to better understand the effects of different fiber dosages on the mechanical behavior of UHPFRC composites. The study successfully replicated various failure mechanisms observed in experiments, including ductile failure with high fiber dosage.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Civil
Mohammed T. Nagib, Mohammed A. Sakr, Saher R. El-khoriby, Tarek M. Khalifa
Summary: This paper presents an experimental investigation on seismically shear-deficient RC shear walls strengthened with UHPFRC layers, showing that the strengthening techniques significantly improve lateral load strength, ductility, and energy dissipation capacities. The UHPFRC strengthening techniques increased the lateral load carrying capacities by 70% to 227% of the original wall, demonstrating their effectiveness in enhancing the performance of RC walls.
ENGINEERING STRUCTURES
(2021)
Review
Construction & Building Technology
Yitao Huang, Steffen Gruenewald, Erik Schlangen, Mladena Lukovic
Summary: This paper reviews the strengthening applications of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) in Reinforced Concrete (RC) structures. It focuses on the shear performance and interface behavior of hybrid structures. The paper highlights the lack of understanding of the interface behavior, overlooked factors, and the need for reliable models and design codes, which hinder the wide application of UHPFRC.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Salam Al-Obaidi, Marco Davolio, Francesco Lo Monte, Ferdinando Costanzi, Massimo Luchini, Patrick Bamonte, Liberato Ferrara
Summary: This paper presents the durability performance of Ultra-High Performance Concrete (UHPC) in harsh environments and the limitations in design standards and knowledge of its durability in real service conditions. A validation study on a full-scale structure using tailored UHPC, called Ultra High Durability Concrete (UHDC), is presented. The study includes periodic assessment and validation tests over two years to evaluate the structural design assumptions and serviceability requirements. The paper highlights key parameters that can affect the performance of UHPC structures.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Construction & Building Technology
Yekai Yang, Chengqing Wu, Zhongxian Liu, Hailiang Wang, Quanchang Ren
Summary: The study introduced a novel 3D-printing ultra-high performance fibre-reinforced concrete (3DP-UHPFRC) and evaluated the effect of fibre content, type, and printing direction on its mechanical properties. The results showed that 3DP-UHPFRC with 1 vol% 6 mm steel fibre had higher flexural strength in the Z-direction compared to previous studies, and the failures could be either ductile or brittle in different directions, allowing for flexible adjustment of printing mode based on engineering requirements. The compressive elastic modulus was found to be anisotropic, while there was little difference in the tensile elastic modulus in each direction.
CEMENT & CONCRETE COMPOSITES
(2022)
Article
Construction & Building Technology
Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Rabar H. Faraj, Ahmed S. Mohammed, Wael Emad, Bassam A. Tayeh, Afonso R. G. Azevedo
Summary: This article reviews the research and development, principles, materials, and properties of Ultra-High-Performance Concrete (UHPC), including its fresh and hardened properties, durability, and applications. It provides important information for advancing the knowledge and promoting further research and applications of UHPC.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Engineering, Civil
Lenganji Simwanda, Adewumi John Babafemi, Nico De Koker, Celeste Viljoen
Summary: This study investigates the uncertainty quantification and reliability analysis of ultra-high-performance fibre reinforced concrete (UHPFRC) beams exposed to fire. Two methodologies are proposed: the stochastic calibration of temperature-dependent thermal properties of UHPFRC using Bayesian inversion, and the computation of UHPFRC beam reliability in fire using Monte Carlo Simulation (MCS). The calibrated posterior probability distributions of temperature-dependent thermal properties of UHPFRC are used to predict temperature distributions that closely match the experimental results. The reliability analysis based on the calibrated thermal properties shows a decrease in reliability index with increasing fire exposure, and the fire resistance is estimated based on a reliability target of 0.7.
Article
Engineering, Civil
Andreas Lampropoulos, Ourania Tsioulou, Anna Mina, Demetris Nicolaides, Michael F. Petrou
Summary: Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) is a high-performance cementitious composite with superior mechanical properties, high energy absorption capacity, and enhanced durability. However, the punching shear performance and the effect of fibres on the punching shear strength of UHPFRC have not been adequately studied, and there is a lack of design provisions, limiting its extensive application in thin elements.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Manufacturing
Yekai Yang, Chengqing Wu, Zhongxian Liu, Hai Zhang
Summary: This study presents an experimental investigation of the triaxial behavior of 3D-printing ultra-high performance fiber-reinforced concrete (3DP-UHPFRC) and compares it with mold-casting ultra-high performance fiber reinforced concrete (MC-UHPFRC). The results show that 3DP-UHPFRC has similar failure modes, mechanical properties, and failure criteria as MC-UHPFRC. Additionally, the fitting effect of the Mohr-Coulomb failure criterion on 3D-printing specimens without steel fiber is poor, while the Power-law and Willam-Warnke failure criteria are suitable for all 3D-printing specimens.
ADDITIVE MANUFACTURING
(2022)
Article
Construction & Building Technology
Arun R. Arunothayan, Behzad Nematollahi, Kamal H. Khayat, Akilesh Ramesh, Jay G. Sanjayan
Summary: The rheological behavior of 3DP-UHPFRC was investigated, and it was found that the inclusion of steel fibers and nano-clay reduced workability and increased static yield stress, dynamic yield stress, and apparent viscosity. However, the effects became negligible at higher fiber or NC contents.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Engineering, Mechanical
Yekai Yang, Chengqing Wu, Zhongxina Liu, Jun Li, Ting Yang, Xiquan Jiang
Summary: This study investigates the characteristics of 3D-printing ultra-high performance fibre reinforced concrete (3DP-UHPFRC) under impact loads using the SHPB tests. The findings show that the failure degree of 3DP-UHPFRC varies in different directions, with the worst degree of failure in the X-direction. The elastic modulus and strain rate effect of 3D-printing specimens exhibit anisotropic characteristics, with the X-direction being more susceptible to deformation. Increasing the impact velocity results in isotropic dynamic peak stresses for 3DP-UHPFRC. Furthermore, the dynamic increase factor (DIF) of the 3D-printing specimens is observed to be anisotropic, with the X-direction exhibiting the most significant strain rate sensitivity.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2022)
Article
Construction & Building Technology
Yitao Huang, Dawei Gu, Shozab Mustafa, Steffen Gruenewald, Mladena Lukovic
Summary: This study investigates the strengthening efficiency of ultra-high performance fiber reinforced concrete (UHPFRC) on shear capacity of concrete bridges through experimental and numerical analysis. The results show that UHPFRC shear strengthening is effective in increasing load and deformational capacity without being affected by environmental exposure.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Construction & Building Technology
Mahmoud H. Akeed, Shaker Qaidi, Hemn U. Ahmed, Wael Emad, Rabar H. Faraj, Ahmed S. Mohammed, Bassam A. Tayeh, Afonso R. G. Azevedo
Summary: This article provides a comprehensive review of the development, principles, raw materials, hydration and microstructure, fresh and hardened properties, durability properties, cost assessment, applications and challenges, mixture design, preparation, mixing, casting, and curing of ultra-high-performance concrete (UHPC). It aims to advance the fundamental knowledge of UHPC and promote further research and applications of UHPC.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Construction & Building Technology
Sayyed Ali Dadvar, Davood Mostofinejad, Hadi Bahmani
Summary: The experimental investigation on axial behavior of circular RC columns strengthened with a combined UHPFRC and GFRP jacketing technique showed significant increases in load-carrying capacity and energy absorption. The use of galvanized midlayer and increasing intermittent GFRP strips also proved to be effective methods in enhancing load-bearing capacity of columns.
ACI STRUCTURAL JOURNAL
(2021)
Article
Engineering, Civil
Nadhim Hamah Sor, Nahla Hilal, Rabar H. Faraj, Hemn Unis Ahmed, Aryan Far H. Sherwani
Summary: This study investigated the relationship between lightweight self compacting concrete made with waste expanded polystyrene beads and their mechanical characteristics, finding that increasing EPS content improved workability but decreased strength, while still meeting the minimum requirements for structural applications. The actual strengths were found to be closest to the ACI 363 standard in comparison to empirical models presented in codes and literature studies.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Rabar H. Faraj, Azad A. Mohammed, Khalid M. Omer, Hemn Unis Ahmed
Summary: The use of recycled aggregates and industrial waste ashes in concrete production can help address resource depletion and environmental pollution. This study proposed a model to predict the compressive strength of self-compacting concrete (SCC) mixes incorporating recycled plastic (RP) aggregates, where the artificial neural network (ANN) model performed the best.
CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY
(2022)
Article
Environmental Sciences
Rabar H. Faraj, Azad A. Mohammed, Khalid M. Omer
Summary: This study proposes four models to predict the compressive strength of self-compacting concrete (SCC) mixes using ground granulated blast furnace slag (GGBFS). Among various statistical evaluations, the artificial neural network (ANN) model performs the best.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Nadhim Hamah Sor, Taghreed Khaleefa Mohammed Ali, Kolimi Shaiksha Vali, Hemn Unis Ahmed, Rabar H. Faraj, Naraindas Bheel, Amir Mosavi
Summary: Sustainable concrete production and recycling of construction wastes are crucial for urban development. This study investigated the use of recycled low-density polyethylene waste as fibers in eco-friendly fiber-reinforced self-compacting concrete (SCC). The incorporation of LDPF negatively affected workability but improved mechanical properties. The optimal ratio of LDPF was found to be 2%, which achieved the desired workability and highest strength with modulus of elasticity. Furthermore, increasing LDPF content in the SCC mixtures resulted in decreased thermal conductivity.
MATERIALS RESEARCH EXPRESS
(2022)
Review
Construction & Building Technology
Rabar H. Faraj, Azad A. Mohammed, Khalid M. Omer
Summary: Nanotechnology has brought unique performance to self-compacting concrete through the inclusion of nanoparticles. This comprehensive review paper examines the effects of different types of nanoparticles on the fresh, mechanical, durability, and microstructure characteristics of various self-compacting concrete composites. The study also proposes models to predict the compressive strength of self-compacting concrete composites modified with nano-silica, the most commonly used nanoparticle. The addition of nanoparticles shows promise in enhancing the strength, durability, and microstructure of self-compacting concrete composites and can be efficiently implemented by the construction industry.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Construction & Building Technology
Hemn Unis Ahmed, Ahmed S. Mohammed, Rabar H. Faraj, Shaker M. A. Qaidi, Azad A. Mohammed
Summary: This paper provides a detailed review on the effect of adding nano-silica (nS) on the compressive strength (CS) of geopolymer concrete (GPC). Various models, including artificial neural network (ANN), M5Ptree, linear regression, nonlinear regression, and multi logistic regression models, were developed to forecast the CS of GPC incorporated nS. Experimental results showed that the addition of nS improves the CS of GPC, and the ANN model performed the best in predicting the CS. Additionally, the alkaline solution to binder ratio, molarity, NaOH content, curing temperature, and ages were identified as significant parameters influencing the CS of GPC incorporated nS.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Review
Engineering, Civil
Hemn Unis Ahmed, Ahmed S. Mohammed, Shaker M. A. Qaidi, Rabar H. Faraj, Nadhim Hamah Sor, Azad A. Mohammed
Summary: Geopolymer concrete, which is an environmentally friendly building material, has its compressive strength influenced by factors such as curing temperature and the ratio of alkaline solution to binder. Multiple models have been developed to predict the compressive strength, with the ANN model performing the best.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2023)
Article
Engineering, Environmental
Hamid Kazemi, Rabar H. Faraj, Wrya Abdullah, Shahriar Shahbazpanahi, Amir Mosavi
Summary: This research investigates the feasibility of using Medium-density fiberboard waste ash (MDFWA) in concrete as a substitute for cement. The results show that the compressive strength of the concrete is increased and the microstructure is improved when a certain proportion of MDFWA is used.
JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION
(2023)
Review
Materials Science, Ceramics
Shaker M. A. Qaidi, Ahmed S. Mohammed, Hemn Unis Ahmed, Rabar H. Faraj, Wael Emad, Bassam A. Tayeh, Fadi Althoey, Osama Zaid, Nadhim Hamah Sor
Summary: This paper presents a comprehensive analysis of the environmental and economic impact, resources, and physicochemical properties of waste rubber, as well as the behaviors and properties of rubberized geopolymer concrete (Ru-GPC). The effect of crumb rubber (CRu) substitution on critical properties is addressed critically. The study also highlights the applications, embodied CO2 emissions, and cost analysis of Ru-GPC.
CERAMICS INTERNATIONAL
(2022)
Review
Construction & Building Technology
Shaker M. A. Qaidi, Dawood Sulaiman Atrushi, Ahmed S. Mohammed, Hemn Unis Ahmed, Rabar H. Faraj, Wael Emad, Bassam A. Tayeh, Hadee Mohammed Najm
Summary: This paper provides a state-of-the-art review of the technical and production properties of ultra-high-performance geopolymer concrete (UHP-GPC), including environmental parameters, mix design, mechanical properties, durability properties, microstructural properties, and the relationship between compressive strength and other properties.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Green & Sustainable Science & Technology
Kawan Ghafor, Hemn Unis Ahmed, Rabar H. Faraj, Ahmed Salih Mohammed, Rawaz Kurda, Warzer Sarwar Qadir, Wael Mahmood, Aso A. Abdalla
Summary: Concrete has high compressive strength and low tensile strength, but reinforced concrete with additives like steel can increase the tensile strength. Engineered cementitious composites address this issue by adding short polymer fibers to the cement-based matrix.
Article
Engineering, Civil
Soran Abdrahman Ahmad, Serwan Khwrshed Rafiq, Rabar H. Faraj
Summary: One interesting way to utilize waste materials is to add them to concrete and mortar as partial replacements. In this study, 123 data with different parameters were collected and analyzed, resulting in the development of a predictive model for compressive strength. The artificial neural network model showed better performance in predicting the compressive strength of mortar mixtures containing fine glass and fly ash compared to other models.
INNOVATIVE INFRASTRUCTURE SOLUTIONS
(2023)
Article
Construction & Building Technology
Peshkawt Yaseen Saleh, Dilshad Kakasor Ismael Jaf, Aso A. Abdalla, Hemn Unis Ahmed, Rabar H. Faraj, Wael Mahmood, Ahmed Salih Mohammed
Summary: Different modeling tools are used to propose analytical models to predict the compressive strength (CS) of ECC mixtures. The artificial neural network (ANN) model is found to be superior with high R-2, RMSE, MAE, and SI. Sensitivity analysis shows that curing time and fly ash-to-cement ratio are essential in forecasting ECC's CS.
STRUCTURAL CONCRETE
(2023)
Article
Construction & Building Technology
Dilshad Kakasor Ismael Jaf, Alan Saeed Abdulrahman, Payam Ismael Abdulrahman, Ahmed Salih Mohammed, Rawaz Kurda, Hemn Unis Ahmed, Rabar H. Faraj
Summary: Environmental issues arise from increased CO2 emissions in global industries due to global warming. Cement production contributes 8-10% of total CO2 emissions. Fly ash is suggested as the best alternative to cement in concrete production. This study investigates the effect of SiO2/CaO ratio in fly ash on the compressive strength of concrete. Mathematical and machine learning models are developed to predict the compressive strength, with the IN model being the most effective. Increasing SiO2/CaO ratio decreases compressive strength up to a certain point, while increasing cement replacement and fly ash content decreases compressive strength.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Bedar Rauf Hassan, Fkrat Latif Hamid, Rabar H. Faraj, Rozhnw Omer Mustafa, Gullan Hamza Omar, Shnyar Anwar Omar
Summary: This research paper focuses on haunched beams, also known as tapered beams, and their structural characteristics and construction challenges. The study includes an experimental phase to investigate the influence of tapered angles and recycled strap fiber on the shear behavior of tapered beams. The results show that as the tapered angles and fiber contents increase, the shear strength of haunched beams also increases.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
